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Yellowstone National Park

Yellowstone National Park is an American national park located in the western United States, largely in the northwest corner of Wyoming and extending into Montana and Idaho. It was established by the 42nd U.S. Congress with the Yellowstone National Park Protection Act and signed into law by President Ulysses S. Grant on March 1, 1872.[6][7][8][9] Yellowstone was the first national park in the U.S. and is also widely held to be the first national park in the world.[10] The park is known for its wildlife and its many geothermal features, especially the Old Faithful geyser, one of its most popular.[11] While it represents many types of biomes, the subalpine forest is the most abundant. It is part of the South Central Rockies forests ecoregion.

Yellowstone National Park
Location of Yellowstone National Park
Yellowstone National Park (the United States)
Location
Nearest townWest Yellowstone, Montana
Coordinates44°35′47″N 110°32′50″W / 44.59639°N 110.54722°W / 44.59639; -110.54722Coordinates: 44°35′47″N 110°32′50″W / 44.59639°N 110.54722°W / 44.59639; -110.54722[2]
Area2,219,791 acres (8,983.18 km2)[3]
Elevation8,104 ft (2,470 m)
EstablishedMarch 1, 1872; 151 years ago (1872-03-01)
Visitors3,806,306 (in 2020)[4]
Governing bodyU.S. National Park Service
Websitewww.nps.gov/yell/
TypeNatural
Criteriavii, viii, ix, x
Designated1978 (2nd session)
Reference no.28[5]
RegionThe Americas
Endangered1995–2003

While Native Americans have lived in the Yellowstone region for at least 11,000 years,[12] aside from visits by mountain men during the early-to-mid-19th century, organized exploration did not begin until the late 1860s. Management and control of the park originally fell under the jurisdiction of the United States Department of the Interior, the first Secretary of the Interior to supervise the park being Columbus Delano. However, the U.S. Army was eventually commissioned to oversee the management of Yellowstone for 30 years between 1886 and 1916.[13] In 1917, administration of the park was transferred to the National Park Service, which had been created the previous year. Hundreds of structures have been built and are protected for their architectural and historical significance, and researchers have examined more than a thousand archaeological sites.

Yellowstone National Park spans an area of 3,468.4 sq mi (8,983 km2),[3] comprising lakes, canyons, rivers, and mountain ranges.[11] Yellowstone Lake is one of the largest high-elevation lakes in North America and is centered over the Yellowstone Caldera, the largest supervolcano on the continent. The caldera is considered a dormant volcano. It has erupted with tremendous force several times in the last two million years.[14] Well over half of the world's geysers[15][16] and hydrothermal features[17] are in Yellowstone, fueled by this ongoing volcanism. Lava flows and rocks from volcanic eruptions cover most of the land area of Yellowstone. The park is the centerpiece of the Greater Yellowstone Ecosystem, the largest remaining nearly-intact ecosystem in the Earth's northern temperate zone.[18] In 1978, Yellowstone was named a UNESCO World Heritage Site.

Hundreds of species of mammals, birds, fish, reptiles, and amphibians have been documented, including several that are either endangered or threatened.[11] The vast forests and grasslands also include unique species of plants. Yellowstone Park is the largest, and most famous megafauna location in the contiguous United States. Grizzly bears, wolves, and free-ranging herds of bison and elk live in this park. The Yellowstone Park bison herd is the oldest and largest public bison herd in the United States. Forest fires occur in the park each year; in the large forest fires of 1988, nearly one-third of the park was burnt. Yellowstone has numerous recreational opportunities, including hiking, camping, boating, fishing, and sightseeing. Paved roads provide close access to the major geothermal areas as well as some of the lakes and waterfalls. During the winter, visitors often access the park by way of guided tours that use either snow coaches or snowmobiles.[19]

History

The park contains the headwaters of the Yellowstone River, from which it takes its historical name. Near the end of the 18th century, French trappers named the river Roche Jaune, which is probably a translation of the Hidatsa name Mi tsi a-da-zi ("Yellow Stone River").[20] Later, American trappers rendered the French name in English as "Yellow Stone". Although it is commonly believed that the river was named for the yellow rocks seen in the Grand Canyon of the Yellowstone, the Native American name source is unclear.[21]

 
Detailed pictorial map from 1904

The human history of the park began at least 11,000 years ago when Native Americans began to hunt and fish in the region. During the construction of the post office in Gardiner, Montana, in the 1950s, an obsidian point of Clovis origin was found that dated from approximately 11,000 years ago.[22] These Paleo-Indians, of the Clovis culture, used the significant amounts of obsidian found in the park to make cutting tools and weapons. Arrowheads made of Yellowstone obsidian have been found as far away as the Mississippi Valley, indicating that a regular obsidian trade existed between local tribes and tribes farther east.[23] When the Lewis and Clark Expedition entered present-day Montana in 1805 they encountered the Nez Perce, Crow, and Shoshone tribes who described to them the Yellowstone region to the south, but they chose not to investigate.[24]

In 1806, John Colter, a member of the Lewis and Clark Expedition, left to join a group of fur trappers. After splitting up with the other trappers in 1807, Colter passed through a portion of what later became the park, during the winter of 1807–1808. He observed at least one geothermal area in the northeastern section of the park, near Tower Fall.[25] After surviving wounds he suffered in a battle with members of the Crow and Blackfoot tribes in 1809, Colter described a place of "fire and brimstone" that most people dismissed as delirium; the supposedly mystical place was nicknamed "Colter's Hell". Over the next 40 years, numerous reports from mountain men and trappers told of boiling mud, steaming rivers, and petrified trees, yet most of these reports were believed at the time to be a myth.[26]

After an 1856 exploration, mountain man Jim Bridger (also believed to be the first or second European American to have seen the Great Salt Lake) reported observing boiling springs, spouting water, and a mountain of glass and yellow rock. These reports were largely ignored because Bridger was a known "spinner of yarns". In 1859, a U.S. Army Surveyor named Captain William F. Raynolds embarked on a two-year survey of the southern central Rockies. After wintering in Wyoming, in May 1860, Raynolds and his party—which included geologist Ferdinand V. Hayden and guide Jim Bridger—attempted to cross the Continental Divide over Two Ocean Plateau from the Wind River drainage in northwest Wyoming. Heavy spring snows prevented their passage but had they been able to traverse the divide, the party would have been the first organized survey to enter the Yellowstone region.[27] The American Civil War hampered further organized explorations until the late 1860s.[28]

 
Ferdinand V. Hayden (1829–1887), an American geologist who convinced Congress to make Yellowstone a national park in 1872

The first detailed expedition to the Yellowstone area was the Cook–Folsom–Peterson Expedition of 1869, which consisted of three privately funded explorers. The Folsom party followed the Yellowstone River to Yellowstone Lake.[29] The members of the Folsom party kept a journal and based on the information it reported, a party of Montana residents organized the Washburn–Langford–Doane Expedition in 1870. It was headed by the surveyor-general of Montana Henry Washburn, and included Nathaniel P. Langford (who later became known as "National Park" Langford) and a U.S. Army detachment commanded by Lt. Gustavus Doane. The expedition spent about a month exploring the region, collecting specimens, and naming sites of interest.[30]

A Montana writer and lawyer named Cornelius Hedges, who had been a member of the Washburn expedition, proposed that the region should be set aside and protected as a national park; he wrote detailed articles about his observations for the Helena Herald newspaper between 1870 and 1871. Hedges essentially restated comments made in October 1865 by acting Montana Territorial Governor Thomas Francis Meagher, who had previously commented that the region should be protected.[31] Others made similar suggestions. An 1871 letter to Ferdinand V. Hayden from Jay Cooke, a businessman who wanted to bring tourists to the region, encouraged him to mention it in his official report of the survey.[32] Cooke wrote that his friend, Congressman William D. Kelley had also suggested "Congress pass a bill reserving the Great Geyser Basin as a public park forever".[33]

Park creation

 
Ferdinand V. Hayden's map of Yellowstone National Park, 1871

In 1871, eleven years after his failed first effort, Ferdinand V. Hayden was finally able to explore the region. With government sponsorship, he returned to the region with a second, larger expedition, the Hayden Geological Survey of 1871. He compiled a comprehensive report, including large-format photographs by William Henry Jackson and paintings by Thomas Moran. The report helped to convince the U.S. Congress to withdraw this region from public auction. On March 1, 1872, President Ulysses S. Grant signed The Act of Dedication[8] law that created Yellowstone National Park.[34]

Hayden, while not the only person to have thought of creating a park in the region, was its first and most enthusiastic advocate.[35] He believed in "setting aside the area as a pleasure ground for the benefit and enjoyment of the people" and warned that there were those who would come and "make merchandise of these beautiful specimens".[35] Worrying the area could face the same fate as Niagara Falls, he concluded the site should "be as free as the air or Water."[35] In his report to the Committee on Public Lands, he concluded that if the bill failed to become law, "the vandals who are now waiting to enter into this wonder-land, will in a single season despoil, beyond recovery, these remarkable curiosities, which have required all the cunning skill of nature thousands of years to prepare".[36][37]

Hayden and his 1871 party recognized Yellowstone as a unique place that should be available for further research. He also was encouraged to preserve it for others to see and experience it as well. In 1873, Congress authorized and funded a survey to find a wagon route to the park from the south which was completed by the Jones Expedition of 1873.[38] Eventually the railroads and, sometime after that, the automobile would make that possible. The park was not set aside strictly for ecological purposes; however, the designation "pleasure ground" was not an invitation to create an amusement park. Hayden imagined something akin to the scenic resorts and baths in England, Germany, and Switzerland.[35]

THE ACT OF DEDICATION[37]

AN ACT to set apart a certain tract of land lying near the headwaters of the Yellowstone River as a public park. Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That the tract of land in the Territories of Montana and Wyoming ... is hereby reserved and withdrawn from settlement, occupancy, or sale under the laws of the United States, and dedicated and set apart as a public park or pleasuring ground for the benefit and enjoyment of the people; and all persons who shall locate, or settle upon, or occupy the same or any part thereof, except as hereinafter provided, shall be considered trespassers and removed there from ...

Approved March 1, 1872.

Signed by:

 
Portrait of Nathaniel P. Langford (1870), the first superintendent of the park[39]

There was considerable local opposition to Yellowstone National Park during its early years. Some of the locals feared that the regional economy would be unable to thrive if there remained strict federal prohibitions against resource development or settlement within park boundaries and local entrepreneurs advocated reducing the size of the park so that mining, hunting, and logging activities could be developed.[40] To this end, numerous bills were introduced into Congress by Montana representatives who sought to remove the federal land-use restrictions.[41]

After the park's official formation, Nathaniel Langford was appointed as the park's first superintendent in 1872 by the Secretary of Interior Columbus Delano, the first overseer and controller of the park.[42] Langford served for five years but was denied a salary, funding, and staff. Langford lacked the means to improve the land or properly protect the park, and without formal policy or regulations, he had few legal methods to enforce such protection. This left Yellowstone vulnerable to poachers, vandals, and others seeking to raid its resources. He addressed the practical problems park administrators faced in the 1872 Report to the Secretary of the Interior[43] and correctly predicted that Yellowstone would become a major international attraction deserving the continuing stewardship of the government. In 1874, both Langford and Delano advocated the creation of a federal agency to protect the vast park, but Congress refused. In 1875, Colonel William Ludlow, who had previously explored areas of Montana under the command of George Armstrong Custer, was assigned to organize and lead an expedition to Montana and the newly established Yellowstone Park. Observations about the lawlessness and exploitation of park resources were included in Ludlow's Report of a Reconnaissance to the Yellowstone National Park. The report included letters and attachments by other expedition members, including naturalist and mineralogist George Bird Grinnell.[44]

 
Great Falls of the Yellowstone, U.S. Geological and Geographic Survey of the Territories (1874–1879), photographer William Henry Jackson

Grinnell documented the poaching of buffalo, deer, elk, and antelope for hides. "It is estimated that during the winter of 1874–1875, not less than 3,000 buffalo and mule deer suffer even more severely than the elk, and the antelope nearly as much."[45]

As a result, Langford was forced to step down in 1877.[46][47] Having traveled through Yellowstone and witnessed land management problems, Philetus Norris volunteered for the position following Langford's exit. Congress finally saw fit to implement a salary for the position, as well as to provide minimal funding to operate the park. Norris used these funds to expand access to the park, building numerous crude roads and facilities.[47]

In 1880, Harry Yount was appointed as a gamekeeper to control poaching and vandalism in the park. Yount had previously spent decades exploring the mountain country of present-day Wyoming, including the Grand Tetons, after joining F V. Hayden's Geological Survey in 1873.[48] Yount is the first national park ranger,[49] and Yount's Peak, at the head of the Yellowstone River, was named in his honor.[50] However, these measures still proved to be insufficient in protecting the park, as neither Norris nor the three superintendents who followed, were given sufficient manpower or resources.

The Northern Pacific Railroad built a train station in Livingston, Montana, connecting to the northern entrance in the early 1880s, which helped to increase visitation from 300 in 1872 to 5,000 in 1883.[51] A line was also extended from Livingston to Gardiner station, where passengers switched to stagecoach.[52] Visitors in these early years faced poor roads and limited services, and most access into the park was on horse or via stagecoach. By 1908 visitation increased enough to attract a Union Pacific Railroad connection to West Yellowstone, though rail visitation fell off considerably by World War II and ceased around the 1960s.

 
 
Left: Thomas Moran painted Tower Creek while on the Hayden Geological Survey of 1871. Right: Travertine Terrace, Mammoth Hot Springs

During the 1870s and 1880s, Native American tribes were effectively excluded from the national park. Under a half-dozen tribes had made seasonal use of the Yellowstone area- the only year-round residents were small bands of Eastern Shoshone known as "Sheepeaters". They left the area under the assurances of a treaty negotiated in 1868, under which the Sheepeaters ceded their lands but retained the right to hunt in Yellowstone. The United States never ratified the treaty and refused to recognize the claims of the Sheepeaters or any other tribe that had used Yellowstone.[53]

The Nez Perce band associated with Chief Joseph, numbering about 750 people, passed through Yellowstone National Park in thirteen days in late August 1877. They were being pursued by the U.S. Army and entered the national park about two weeks after the Battle of the Big Hole. Some of the Nez Perce were friendly to the tourists and other people they encountered in the park; some were not. Nine park visitors were briefly taken captive. Despite Joseph and other chiefs ordering that no one should be harmed, at least two people were killed and several wounded.[54][55] One of the areas where encounters occurred was in Lower Geyser Basin and east along a branch of the Firehole River to Mary Mountain and beyond.[54] That stream is still known as Nez Perce Creek.[56] A group of Bannocks entered the park in 1878, alarming park Superintendent Philetus Norris. In the aftermath of the Sheepeater Indian War of 1879, Norris built a fort to prevent Native Americans from entering the national park.[53][55]

 
Fort Yellowstone (circa 1910), formerly a U.S. Army post, now serves as park headquarters.

Ongoing poaching and destruction of natural resources continued unabated until the U.S. Army arrived at Mammoth Hot Springs in 1886 and built Camp Sheridan. Over the next 22 years, as the army constructed permanent structures, Camp Sheridan was renamed Fort Yellowstone.[57] On May 7, 1894, the Boone and Crockett Club, acting through the personality of George G. Vest, Arnold Hague, William Hallett Phillips, W. A. Wadsworth, Archibald Rogers, Theodore Roosevelt, and George Bird Grinnell were successful in carrying through the Park Protection Act, which saved the park.[58] The Lacey Act of 1900 provided legal support for the officials prosecuting poachers. With the funding and manpower necessary to keep a diligent watch, the army developed its own policies and regulations that permitted public access while protecting park wildlife and natural resources. When the National Park Service was created in 1916, many of the management principles developed by the army were adopted by the new agency.[57] The army turned control over to the National Park Service on October 31, 1918.[59]

In 1898, the naturalist John Muir described the park as follows: "However orderly your excursions or aimless, again and again amid the calmest, stillest scenery you will be brought to a standstill hushed and awe-stricken before phenomena wholly new to you. Boiling springs and huge deep pools of purest green and azure water, thousands of them, are plashing and heaving in these high, cool mountains as if a fierce furnace fire were burning beneath each one of them; and a hundred geysers, white torrents of boiling water and steam, like inverted waterfalls, are ever and anon rushing up out of the hot, black underworld."[60]

Later history

 
Superintendent Horace M. Albright and black bears (1922). Tourists often fed black bears in the park's early years, with 527 injuries reported from 1931 to 1939.[61]

By 1915, 1,000 automobiles per year were entering the park, resulting in conflicts with horses and horse-drawn transportation. Horse travel on roads was eventually prohibited.[62]

The Civilian Conservation Corps (CCC), a New Deal relief agency for young men, played a major role between 1933 and 1942 in developing Yellowstone facilities. CCC projects included reforestation, campground development of many of the park's trails and campgrounds, trail construction, fire hazard reduction, and fire-fighting work. The CCC built the majority of the early visitor centers, campgrounds, and the current system of park roads.[63]

During World War II, tourist travel fell sharply, staffing was cut, and many facilities fell into disrepair.[64] By the 1950s, visitation increased tremendously in Yellowstone and other national parks. To accommodate the increased visitation, park officials implemented Mission 66, an effort to modernize and expand park service facilities. Planned to be completed by 1966, in honor of the 50th anniversary of the founding of the National Park Service, Mission 66 construction diverged from the traditional log cabin style with design features of a modern style.[65] During the late 1980s, most construction styles in Yellowstone reverted to the more traditional designs. After the enormous forest fires of 1988 damaged much of Grant Village, structures there were rebuilt in the traditional style. The visitor center at Canyon Village, which opened in 2006, incorporates a more traditional design as well.[66]

 
The Roosevelt Arch in Gardiner, Montana, at the north entrance

The 1959 Hebgen Lake earthquake just west of Yellowstone at Hebgen Lake damaged roads and some structures in the park. In the northwest section of the park, new geysers were found, and many existing hot springs became turbid.[67] It was the most powerful earthquake to hit the region in recorded history.

In 1963, after several years of public controversy regarding the forced reduction of the elk population in Yellowstone, the United States Secretary of the Interior Stewart Udall appointed an advisory board to collect scientific data to inform future wildlife management of the national parks. In a paper known as the Leopold Report, the committee observed that culling programs at other national parks had been ineffective, and recommended the management of Yellowstone's elk population.[68]

The wildfires during the summer of 1988 were the largest in the history of the park. Approximately 793,880 acres (3,210 km2; 1,240 sq mi) or 36% of the parkland was impacted by the fires, leading to a systematic re-evaluation of fire management policies. The fire season of 1988 was considered normal until a combination of drought and heat by mid-July contributed to an extreme fire danger. On "Black Saturday", August 20, 1988, strong winds expanded the fires rapidly, and more than 150,000 acres (610 km2; 230 sq mi) burned.[69]

 
Pictorial map by Heinrich C. Berann (1991); scale exaggerated

The expansive cultural history of the park has been documented by the 1,000 archeological sites that have been discovered. The park has 1,106 historic structures and features, and of these Obsidian Cliff and five buildings have been designated National Historic Landmarks.[11] Yellowstone was designated an International Biosphere Reserve on October 26, 1976, and a UN World Heritage Site on September 8, 1978. The park was placed on the List of World Heritage in Danger from 1995 to 2003 due to the effects of tourism, infection of wildlife, and issues with invasive species.[70] In 2010, Yellowstone National Park was honored with its own quarter under the America the Beautiful Quarters Program.[71]

Justin Ferrell explores three moral sensibilities that motivated activists in dealing with Yellowstone. First came the utilitarian vision of maximum exploitation of natural resources, a characteristic of developers in the late 19th century. Second was the spiritual vision of nature inspired by Romanticism and the transcendentalists in the mid-19th century. The twentieth century saw the biocentric moral vision that focuses on the health of the ecosystem as theorized by Aldo Leopold, which led to the expansion of federally protected areas and the surrounding ecosystems.[72]

Heritage and Research Center

The Heritage and Research Center is located at Gardiner, Montana, near the north entrance to the park.[73] The center is home to the Yellowstone National Park's museum collection, archives, research library, historian, archeology lab, and herbarium. The Yellowstone National Park Archives maintain collections of historical records of Yellowstone and the National Park Service. The collection includes the administrative records of Yellowstone, as well as resource management records, records from major projects, and donated manuscripts and personal papers. The archives are affiliated with the National Archives and Records Administration.[74][75]

Geography

 
Official park map c. 2020 (click on map to enlarge)
 
Satellite image of Yellowstone National Park in 2020
 
Interactive map of Yellowstone National Park

Approximately 96 percent of the land area of Yellowstone National Park is located within the state of Wyoming.[11] Another three percent is within Montana, with the remaining one percent in Idaho. The park is 63 miles (101 km) north to south, and 54 miles (87 km) west to east by air. Yellowstone is 2,219,789 acres (8,983 km2; 3,468 sq mi)[3] in area, larger than either of the states of Rhode Island or Delaware. Rivers and lakes cover five percent of the land area, with the largest water body being Yellowstone Lake at 87,040 acres (352 km2; 136 sq mi). Yellowstone Lake is up to 400 feet (120 m) deep and has 110 miles (180 km) of shoreline. At an elevation of 7,733 feet (2,357 m) above sea level, Yellowstone Lake is the largest high-elevation lake in North America. Forests comprise 80 percent of the land area of the park; most of the rest is grassland.[11]

The Continental Divide of North America runs diagonally through the southwestern part of the park. The divide is a topographic feature that separates the Pacific Ocean and Atlantic Ocean water drainages. About one-third of the park lies on the west side of the divide. The origins of the Yellowstone and Snake Rivers are near each other but on opposite sides of the divide. As a result, the waters of the Snake River flow to the Pacific Ocean, while those of the Yellowstone find their way to the Gulf of Mexico.[76]

The park sits on the Yellowstone Plateau, at an average elevation of 8,000 feet (2,400 m) above sea level. The plateau is bounded on nearly all sides by mountain ranges of the Middle Rocky Mountains, which range from 9,000 to 11,000 feet (2,700 to 3,400 m) in elevation. The highest point in the park is atop Eagle Peak (11,358 feet or 3,462 metres) and the lowest is along Reese Creek (5,282 feet or 1,610 metres).[11] Nearby mountain ranges include the Gallatin Range to the northwest, the Beartooth Mountains in the north, the Absaroka Range to the east, the Teton Range to the south, and the Madison Range to the west. The most prominent summit on the Yellowstone Plateau is Mount Washburn at 10,243 feet (3,122 m).[77]

Yellowstone National Park has one of the world's largest petrified forests, trees which were long ago buried by ash and soil and transformed from wood to mineral materials. This ash and other volcanic debris are believed to have come from the park area itself as the central part of Yellowstone is the massive caldera of a supervolcano. The park contains 290 waterfalls of at least 15 feet (4.6 m), the highest being the Lower Falls of the Yellowstone River at 308 feet (94 m).[11]

Three deep canyons are located in the park, cut through the volcanic tuff of the Yellowstone Plateau by rivers over the last 640,000 years. The Lewis River flows through Lewis Canyon in the south, and the Yellowstone River has carved two colorful canyons, the Grand Canyon of the Yellowstone and the Black Canyon of the Yellowstone in its journey north.[77][78][79]

Geology

Volcanism

 
Columnar basalt near Tower Fall; large floods of basalt and other lava types preceded mega-eruptions of superheated ash and pumice.
 
Caldera rim on the horizon south of Yellowstone Lake.

Yellowstone is at the northeastern end of the Snake River Plain, a great U-shaped arc through the mountains that extends from Boise, Idaho some 400 miles (640 km) to the west.

The volcanism of Yellowstone is believed to be linked to the somewhat older volcanism of the Snake River plain. Yellowstone is thus the active part of a hotspot that has moved northeast over time.[80] The origin of this hotspot volcanism is disputed.[81] One theory holds that a mantle plume has caused the Yellowstone hotspot to migrate northeast, while another theory explains migrating hotspot volcanism as the result of the fragmentation and dynamics of the subducted Farallon Plate in Earth's interior.[81][82]

The Yellowstone Caldera is the largest volcanic system in North America, and worldwide it is only rivaled by the Lake Toba Caldera on Sumatra. It has been termed a "supervolcano" because the caldera was formed by exceptionally large explosive eruptions. The magma chamber that lies under Yellowstone is estimated to be a single connected chamber, about 37 miles (60 km) long, 18 miles (29 km) wide, and 3 to 7 miles (5 to 12 km) deep.[83] The current caldera was created by a cataclysmic eruption that occurred 640,000 years ago, which released more than 240 cubic miles (1,000 km³) of ash, rock and pyroclastic materials.[84] This eruption was more than 1,000 times larger than the 1980 eruption of Mount St. Helens.[85] It produced a caldera nearly 5/8 of a mile (1 km) deep and 45 by 28 miles (72 by 45 km) in area and deposited the Lava Creek Tuff, a welded tuff geologic formation. The most violent known eruption, which occurred 2.1 million years ago, ejected 588 cubic miles (2,450 km³) of volcanic material and created the rock formation known as the Huckleberry Ridge Tuff and created the Island Park Caldera.[86] A smaller eruption ejected 67 cubic miles (280 km³) of material 1.3 million years ago, forming the Henry's Fork Caldera and depositing the Mesa Falls Tuff.[85]

Each of the three climactic eruptions released vast amounts of ash that blanketed much of central North America, falling many hundreds of miles away. The amount of ash and gases released into the atmosphere probably caused significant impacts on world weather patterns and led to the extinction of some species, primarily in North America.[87]

 
Boardwalks allow visitors to safely approach the thermal features, such as Grand Prismatic Spring.

A subsequent caldera-forming eruption occurred about 160,000 years ago. It formed the relatively small caldera that contains the West Thumb of Yellowstone Lake. Since the last supereruption, a series of smaller eruptive cycles between 640,000 and 70,000 years ago, has nearly filled in the Yellowstone Caldera with 80 different eruptions of rhyolitic lavas such as those that can be seen at Obsidian Cliffs and basaltic lavas which can be viewed at Sheepeater Cliff. Lava strata are most easily seen at the Grand Canyon of the Yellowstone, where the Yellowstone River continues to carve into the ancient lava flows. The canyon is a classic V-shaped valley, indicative of river-type erosion rather than erosion caused by glaciation.[86]

Each eruption is part of an eruptive cycle that climaxes with the partial collapse of the roof of the volcano's partially emptied magma chamber. This creates a collapsed depression, called a caldera, and releases vast amounts of volcanic material, usually through fissures that ring the caldera. The time between the last three cataclysmic eruptions in the Yellowstone area has ranged from 600,000 to 800,000 years, but the small number of such climactic eruptions cannot be used to make an accurate prediction for future volcanic events.[88]

Geysers and the hydrothermal system

 
Old Faithful erupts approximately every 90 minutes.
 
Steamboat Geyser is the world's largest active geyser.

The most famous geyser in the park, and perhaps the world, is Old Faithful geyser, located in Upper Geyser Basin. Castle Geyser, Lion Geyser, Beehive Geyser, Grand Geyser (the world's tallest predictable geyser), Giant Geyser (the world's most voluminous geyser), Riverside Geyser and numerous other geysers are in the same basin. The park contains the tallest active geyser in the world—Steamboat Geyser in the Norris Geyser Basin. A study that was completed in 2011 found that at least 1283 geysers have erupted in Yellowstone. Of these, an average of 465 are active in a given year.[89][90] Yellowstone contains at least 10,000 thermal features altogether, including geysers, hot springs, mudpots, and fumaroles.[91] Over half of the world's geysers and hydrothermal features are concentrated in Yellowstone.[92][17]

In May 2001, the U.S. Geological Survey, Yellowstone National Park, and the University of Utah created the Yellowstone Volcano Observatory (YVO), a partnership for long-term monitoring of the geological processes of the Yellowstone Plateau volcanic field, for disseminating information concerning the potential hazards of this geologically active region.[93]

In 2003, changes at the Norris Geyser Basin resulted in the temporary closure of some trails in the basin. New fumaroles were observed, and several geysers showed enhanced activity and increasing water temperatures. Several geysers became so hot that they were transformed into purely steaming features; the water had become superheated and they could no longer erupt normally.[94] This coincided with the release of reports of a multiple year United States Geological Survey research project which mapped the bottom of Yellowstone Lake and identified a structural dome that had uplifted at some time in the past. Research indicated that these uplifts posed no immediate threat of a volcanic eruption, since they may have developed long ago, and there had been no temperature increase found near the uplifts.[95] On March 10, 2004, a biologist discovered 5 dead bison which apparently had inhaled toxic geothermal gases trapped in the Norris Geyser Basin by a seasonal atmospheric inversion. This was closely followed by an upsurge in earthquake activity in April 2004.[96] In 2006, it was reported that the Mallard Lake Dome and the Sour Creek Dome—areas that have long been known to show significant changes in their ground movement—had risen at a rate of 1.5 to 2.4 inches (3.8 to 6.1 cm) per year from mid–2004 through 2006. As of late 2007, the uplift has continued at a reduced rate.[97][98] These events inspired a great deal of media attention and speculation about the geologic future of the region. Experts responded to the conjecture by informing the public that there was no increased risk of a volcanic eruption in the near future.[99] However, these changes demonstrate the dynamic nature of the Yellowstone hydrothermal system.

Earthquakes

 
Infrastructure damage at Hebgen Lake due to the 7.2 magnitude earthquake of 1959

Yellowstone experiences thousands of small earthquakes every year, virtually all of which are undetectable to people. There have been six earthquakes with at least magnitude 6 or greater in historical times, including the 7.2‑magnitude Hebgen Lake earthquake which occurred just outside the northwest boundary of the park in 1959.[100] This quake triggered a huge landslide, which caused a partial dam collapse on Hebgen Lake; immediately downstream, the sediment from the landslide dammed the river and created a new lake, known as Earthquake Lake. Twenty-eight people were killed, and property damage was extensive in the immediate region. The earthquake caused some geysers in the northwestern section of the park to erupt, large cracks in the ground formed and emitted steam, and some hot springs that normally have clear water turned muddy.[67] A 6.1‑magnitude earthquake struck inside the park on June 30, 1975, but the damage was minimal.

For three months in 1985, 3,000 minor earthquakes were detected in the northwestern section of the park, during what has been referred to as an earthquake swarm, and has been attributed to minor subsidence of the Yellowstone caldera.[85] Beginning on April 30, 2007, 16 small earthquakes with magnitudes up to 2.7 occurred in the Yellowstone Caldera for several days. These swarms of earthquakes are common, and there have been 70 such swarms between 1983 and 2008.[101] In December 2008, over 250 earthquakes were measured over four days under Yellowstone Lake, the largest measuring a magnitude of 3.9.[102] In January 2010, more than 250 earthquakes were detected over two days.[103] Seismic activity in Yellowstone National Park continues and is reported hourly by the Earthquake Hazards Program of the U.S. Geological Survey.[104]

On March 30, 2014, a magnitude 4.8 earthquake struck almost the very middle of Yellowstone near the Norris Basin at 6:34 am; reports indicated no damage. This was the largest earthquake to hit the park since February 22, 1980.[105]

Biology and ecology

 
Meadow in Yellowstone National Park

Yellowstone National Park is the centerpiece of the 20 million acres (80,940 km2; 31,250 sq mi) Greater Yellowstone Ecosystem, a region that includes Grand Teton National Park, adjacent National Forests and expansive wilderness areas in those forests. The ecosystem is the largest remaining continuous stretch of mostly undeveloped pristine land in the contiguous United States, considered the world's largest intact ecosystem in the northern temperate zone.[18] With the successful wolf reintroduction program, which began in the 1990s, virtually all the original faunal species known to inhabit the region when white explorers first entered the area can be found there.[citation needed]

Flora

Over 1,700 species of trees and other vascular plants are native to the park. Another 170 species are considered to be exotic species and are non-native. Of the eight conifer tree species documented, Lodgepole Pine forests cover 80% of the total forested areas.[11] Other conifers, such as Subalpine Fir, Engelmann Spruce, Rocky Mountain Douglas-fir and Whitebark Pine, are found in scattered groves throughout the park. As of 2007,[needs update] the whitebark pine is threatened by a fungus known as white pine blister rust; however, this is mostly confined to forests well to the north and west. In Yellowstone, about seven percent of the whitebark pine species have been impacted with the fungus, compared to nearly complete infestations in northwestern Montana.[106] Quaking Aspen and willows are the most common species of deciduous trees. The aspen forests have declined significantly since the early 20th century, but scientists at Oregon State University attribute the recent recovery of the aspen to the reintroduction of wolves which has changed the grazing habits of local elk.[107]

 
Yellowstone sand verbena are endemic to Yellowstone's lakeshores.

There are dozens of species of flowering plants that have been identified, most of which bloom between May and September.[108] The Yellowstone sand verbena is a rare flowering plant found only in Yellowstone. It is closely related to species usually found in much warmer climates, making the sand verbena an enigma. The estimated 8,000 examples of this rare flowering plant all make their home in the sandy soils on the shores of Yellowstone Lake, well above the waterline.[109]

 
Microbial mat in cooled geyser water, Upper Geyser Basin.
 
Orange and brown-tinted microbes growing in sulfur-rich waters near Anemone Geyser.

In Yellowstone's hot waters, bacteria form mats of bizarre shapes consisting of trillions of individuals. These bacteria are some of the most primitive life forms on earth. Flies and other arthropods live on the mats, even in the middle of the bitterly cold winters. Initially, scientists thought that microbes there gained sustenance only from sulfur. In 2005 researchers from the University of Colorado at Boulder discovered that the sustenance for at least some of the diverse hyperthermophilic species is molecular hydrogen.[110]

Thermus aquaticus is a bacterium found in the Yellowstone hot springs that produces an important enzyme (Taq polymerase) that is easily replicated in the lab and is useful in replicating DNA as part of the polymerase chain reaction (PCR) process. The retrieval of these bacteria can be achieved with no impact on the ecosystem. Other bacteria in the Yellowstone hot springs may also prove useful to scientists who are searching for cures for various diseases.[111] In 2016, researchers from Uppsala University reported the discovery of a class of thermophiles, Hadesarchaea, in Yellowstone's Culex Basin. These organisms are capable of converting carbon monoxide and water to carbon dioxide and hydrogen.[112][113]

Non-native plants sometimes threaten native species by using up nutrient resources. Though exotic species are most commonly found in areas with the greatest human visitation, such as near roads and at major tourist areas, they have also spread into the backcountry. Generally, most exotic species are controlled by pulling the plants out of the soil or by spraying, both of which are time-consuming and expensive.[114]

Fauna

Yellowstone is widely considered to be the finest megafauna wildlife habitat in the lower 48 states. There are almost 60 species of mammals in the park, including the Rocky Mountain wolf, coyote, the Canadian lynx, cougars, and black and grizzly bears.[11] Other large mammals include the bison (often referred to as buffalo), elk, moose, mule deer, white-tailed deer, mountain goat, pronghorn, and bighorn sheep.

The Yellowstone Park bison herd is the largest public herd of American bison in the United States. Bison once numbered between 30 and 60 million individuals throughout North America, and Yellowstone remains one of their last strongholds. Their populations had increased from less than 50 in the park in 1902 to 4,000 by 2003. The Yellowstone Park bison herd reached a peak in 2005 with 4,900 animals. Despite a summer estimated population of 4,700 in 2007, the number dropped to 3,000 in 2008 after a harsh winter and controversial brucellosis management strategies which sent hundreds to slaughter.[115]

 
Elk mother nursing her calf

The Yellowstone Park bison herd is believed to be one of only four free-roaming and genetically pure herds on public lands in North America. The other three herds are the Henry Mountains bison herd of Utah, at Wind Cave National Park in South Dakota, and in Elk Island National Park in Alberta.[116]

The relatively large bison populations are a concern for ranchers, who fear that the species can transmit bovine diseases to their domesticated cousins. About half of Yellowstone's bison have been exposed to brucellosis, a bacterial disease that came to North America with European cattle that may cause cattle to miscarry. The disease has little effect on park bison, and no reported cases of transmission from wild bison to domestic livestock have been filed. However, the Animal and Plant Health Inspection Service (APHIS) has stated that bison are the "likely source" of the spread of the disease in cattle in Wyoming and North Dakota. Elk also carry the disease and are believed to have transmitted the infection to horses and cattle.[117]

To combat the perceived threat of brucellosis transmission to cattle, national park personnel regularly corral bison herds back into the park when they venture outside of the area's borders. During the winter of 1996–97, the bison herd was so large that 1,079 bison that had exited the park were either shot or sent to slaughter.[117] Animal rights activists argue that this is a cruel practice and that the possibility for disease transmission is not as great as some ranchers maintain. Ecologists point out that the bison are merely traveling to seasonal grazing areas that lie within the Greater Yellowstone Ecosystem that have been converted to cattle grazing, some of which are within National Forests and are leased to private ranchers. APHIS has stated that with vaccinations and other means, brucellosis can be eliminated from the bison and elk herds throughout Yellowstone.[117]

 
A reintroduced wolf in Yellowstone National Park

Starting in 1914, to protect elk populations, the U.S. Congress appropriated funds to be used for "destroying wolves, prairie dogs, and other animals injurious to agriculture and animal husbandry" on public lands. Park Service hunters carried out these orders, and by 1926 they had killed 136 wolves. Gradually, wolves were virtually eliminated from Yellowstone.[118] Further exterminations continued until the National Park Service ended the practice in 1935. With the passing of the Endangered Species Act in 1973, the wolf was one of the first mammal species listed.[118] After the wolves were extirpated from Yellowstone, the coyote then became the park's top canine predator. Since the coyote is not able to bring down large animals, this lack of an apex predator resulted in a marked increase in lame and sick megafauna.[citation needed]

By the 1990s, the Federal government had reversed its views on wolves. In a controversial decision by the U.S. Fish and Wildlife Service (which oversees threatened and endangered species), northwestern wolves imported from Canada were reintroduced into the park. Reintroduction efforts have been successful, with populations remaining relatively stable. A survey conducted in 2005 reported that there were 13 wolf packs, totaling 118 individuals in Yellowstone and 326 in the entire ecosystem. These park figures were lower than those reported in 2004, but may be attributable to wolf migration to other nearby areas as suggested by the substantial increase in the Montana population during that interval.[119] Almost all the wolves documented were descended from the 66 wolves reintroduced in 1995–96.[119] The recovery of populations throughout the states of Wyoming, Montana, and Idaho has been so successful that on February 27, 2008, the U.S. Fish and Wildlife Service removed the Northern Rocky Mountain wolf population from the endangered species list.[120]

 
Black bear and cub near Tower Fall

Black bears are common in the park and were a park symbol due to visitor interaction with the bears starting in 1910. Feeding and close contact with bears has not been permitted since the 1960s to reduce their desire for human foods.[121] Yellowstone is one of the few places in the United States where black bears can be seen coexisting with grizzly bears.[121] Black bear observations occur most often in the park's northern ranges, and in the Bechler area which is in the park's southwestern corner.[122]

As of 2017, an estimated 700 grizzly bears were living in the Greater Yellowstone Ecosystem,[123] with about 150 grizzlies living wholly or partially within Yellowstone National Park.[124] The grizzly was initially listed as a threatened species in the contiguous United States on July 28, 1975, by the Fish and Wildlife Service. The grizzly bear was taken off the endangered species list in 2007.[125] Opponents of delisting the grizzly expressed concerns that states might once again allow hunting and that better conservation measures were needed to ensure a sustainable population.[126] A federal district judge overturned the delisting ruling in 2009, reinstating the grizzly; however, the grizzly was once again removed from the list in 2017.[125] In September 2018, a US district judge ruled that the grizzly's protections must be restored in full, arguing the Fish and Wildlife Service was mistaken in removing the bear from the threatened status list.[127] Regardless of the rulings, hunting is prohibited within Yellowstone National Park. Hunters who legally hunt animals outside park boundaries may transport the carcass through the park with a permit.[128]

 
Elk in Hayden Valley

Population figures for elk are more than 30,000—the largest population of any large mammal species in Yellowstone. The northern herd has decreased enormously since the mid‑1990s; this has been attributed to wolf predation and causal effects such as elk using more forested regions to evade predation, consequently making it harder for researchers to accurately count them.[129] The northern herd migrates west into southwestern Montana in the winter. The southern herd migrates southward, and the majority of this elk winter on the National Elk Refuge, immediately southeast of Grand Teton National Park. The southern herd migration is the largest mammalian migration remaining in the U.S. outside of Alaska.[citation needed]

In 2003 the tracks of one female lynx and her cub were spotted and followed for over 2 miles (3.2 km). Fecal material and other evidence obtained were tested and confirmed to be those of a lynx. No visual confirmation was made, however. Lynx have not been seen in Yellowstone since 1998, though DNA taken from hair samples obtained in 2001 confirmed that lynx were at least transient to the park.[130] Other less commonly seen mammals include the mountain lion and wolverine. The mountain lion has an estimated population of only 25 individuals parkwide.[131] Accurate population figures for the wolverine are not known.[132] These uncommon and rare mammals provide insight into the health of protected lands such as Yellowstone and help managers make determinations as to how best to preserve habitats.

 
Pronghorn are commonly found on the grasslands in the park.

Eighteen species of fish live in Yellowstone, including the core range of the Yellowstone cutthroat trout—a fish highly sought by anglers.[11][133] The Yellowstone cutthroat trout has faced several threats since the 1980s, including the suspected illegal introduction into Yellowstone Lake of lake trout, an invasive species which consume the smaller cutthroat trout.[134] Although lake trout were established in Shoshone and Lewis lakes (on the Snake River drainage) after U.S. Government stocking operations in 1890, it was never officially introduced into the Yellowstone River drainage.[135] The cutthroat trout has also faced an ongoing drought, as well as the accidental introduction of a parasite—whirling disease—which causes a terminal nervous system disease in younger fish. Since 2001, all native sport fish species caught in Yellowstone waterways are subject to catch and release regulations.[133]

Yellowstone is also home to seven species of reptiles, including the painted turtle, rubber Rubber boa, and prairie rattlesnake, bullsnake, sagebrush lizard, valley garter snake and wandering garter snake and four species of amphibians, including the boreal chorus frog, tiger salamander, western toad and columbia spotted frog.[136]

Three hundred eleven species of birds have been reported, almost half of which nest in Yellowstone.[11] In 1999, twenty-six pairs of nesting bald eagle were documented. Extremely rare sightings of whooping cranes have been recorded, however, only three examples of this species are known to live in the Rocky Mountains, out of 385 known worldwide.[137] Other birds, considered to be species of special concern because of their rarity in Yellowstone, include the common loon, harlequin duck, osprey, peregrine falcon and the trumpeter swan.[138]

Forest fires

 
Fire in Yellowstone National Park

As wildfire is a natural part of most ecosystems, plants that are indigenous to Yellowstone have adapted in a variety of ways. Douglas-fir have a thick bark that protects the inner section of the tree from most fires. Lodgepole Pines—the most common tree species in the park—generally have cones that are only opened by the heat of a fire. Their seeds are held in place by a tough resin, and fire assists in melting the resin, allowing the seeds to disperse. Fire clears out dead and downed wood, providing fewer obstacles for lodgepole pines to flourish. Subalpine Fir, Engelmann Spruce, Whitebark Pine, and other species tend to grow in colder and moister areas, where the fire is less likely to occur. Aspen trees sprout new growth from their roots, and even if a severe fire kills the tree above ground, the roots often survive unharmed because they are insulated from the heat by soil.[139] The National Park Service estimates that in natural conditions, grasslands in Yellowstone burned an average of every 20 to 25 years, while forests in the park would experience fire about every 300 years.[139]

About thirty-five natural forest fires are ignited each year by lightning, while another six to ten are started by people—in most cases by accident. Yellowstone National Park has three fire lookout towers, each staffed by trained firefighters. The easiest one to reach is atop Mount Washburn, which has interpretive exhibits and an observation deck open to the public.[140] The park also monitors fire from the air and relies on visitor reports of smoke and/or flames.[141] Fire towers are staffed almost continuously from late June to mid-September—the primary fire season. Fires burn with the greatest intensity in the late afternoon and evening. Few fires burn more than 100 acres (40 ha), and the vast majority of fires reach only a little over an acre (0.5 ha) before they burn themselves out.[142] Fire management focuses on monitoring dead and down wood quantities, soil, and tree moisture, and the weather, to determine those areas most vulnerable to fire should one ignite. The current policy is to suppress all human-caused fires and to evaluate natural fires, examining the benefit or detriment they may pose to the ecosystem. If a fire is considered to be an immediate threat to people and structures, or will burn out of control, then fire suppression is performed.[143]

 
Wildfire in Yellowstone National Park produces a pyrocumulus cloud.

To minimize the chances of out-of-control fires and threats to people and structures, park employees do more than just monitor the potential for fire. Controlled burns are prescribed fires that are deliberately started to remove dead timber under conditions that allow firefighters an opportunity to carefully control where and how much wood is consumed. Natural fires are sometimes considered prescribed fires if they are left to burn. In Yellowstone, unlike some other parks, there have been very few fires deliberately started by employees as prescribed burns. However, over the last 30 years, over 300 natural fires have been allowed to burn naturally. In addition, firefighters remove dead and down wood and other hazards from areas where they will be a potential fire threat to lives and property, reducing the chances of fire danger in these areas.[144] Fire monitors also regulate fire through educational services to the public and have been known to temporarily ban campfires from campgrounds during periods of high fire danger. The common notion in early United States land management policies was that all forest fires were bad. The fire was seen as a purely destructive force and there was little understanding that it was an integral part of the ecosystem. Consequently, until the 1970s, when a better understanding of wildfire was developed, all fires were suppressed. This led to an increase in dead and dying forests, which would later provide the fuel load for fires that would be much harder, and in some cases, impossible to control. The latest Fire Management Plan (2014) allows natural fires to burn if they posed no immediate threat to lives and property.[145]

 
A crown fire approaches the Old Faithful complex on September 7, 1988.

The spring season of 1988 was wet, but by summer, drought began moving in throughout the northern Rockies, creating the driest year on record to that point. Grasses and plants which grew well in the early summer from the abundant spring moisture produced plenty of grass, which soon turned to dry tinder. The National Park Service began firefighting efforts to keep the fires under control, but the extreme drought made suppression difficult. Between July 15 and 21, 1988, fires quickly spread from 8,500 acres (3,400 ha; 13.3 sq mi) throughout the entire Yellowstone region, which included areas outside the park, to 99,000 acres (40,000 ha; 155 sq mi) on the park land alone. By the end of the month, the fires were out of control. Large fires burned together, and on August 20, 1988, the single worst day of the fires, more than 150,000 acres (61,000 ha; 230 sq mi) were consumed. Seven large fires were responsible for 95% of the 793,000 acres (321,000 ha; 1,239 sq mi) that were burned over the next couple of months. The cost of 25,000 firefighters and U.S. military forces participating in the suppression efforts was 120 million dollars. By the time winter brought snow that helped extinguish the last flames, the fires had destroyed 67 structures and caused several million dollars in damage.[69] Though no civilians died, two personnel associated with the firefighting efforts were killed.[146]

Contrary to media reports and speculation at the time, the fires killed very few park animals—surveys indicated that only about 345 elk (of an estimated 40,000–50,000), 36 deer, 12 moose, 6 black bears, and 9 bison had perished. Changes in fire management policies were implemented by land management agencies throughout the United States, based on knowledge gained from the 1988 fires and the evaluation of scientists and experts from various fields. By 1992, Yellowstone had adopted a new fire management plan which observed stricter guidelines for the management of natural fires.[69]

Climate and weather

 
Winter scene in Yellowstone
 

Yellowstone's climate is greatly influenced by altitude, with lower elevations generally found to be warmer year-round. The record high temperature was 99 °F (37 °C) in 2002, while the coldest temperature recorded is −66 °F (−54 °C) in 1933.[11] During the summer months of June to early September, daytime highs are normally in the 70 to 80 °F (21 to 27 °C) range, while nighttime lows can go to below freezing (0 °C), especially at higher altitudes. Summer afternoons are frequently accompanied by thunderstorms. Spring and fall temperatures range between 30 and 60 °F (−1 and 16 °C) with nights in the teens to single digits (−5 to −20 °C). Winter in Yellowstone is accompanied by high temperatures usually between zero and 20 °F (−20 to −5 °C) and nighttime temperatures below 0  °F (−18 °C) for most of the winter.[147]

Precipitation in Yellowstone is highly variable and ranges from 15 inches (380 mm) annually near Mammoth Hot Springs, to 80 inches (2,000 mm) in the southwestern sections of the park. The precipitation of Yellowstone is greatly influenced by the moisture channel formed by the Snake River Plain to the west that was, in turn, formed by Yellowstone itself. Snow is possible in any month of the year, but most common between November and April, with averages of 150 inches (3,800 mm) annually around Yellowstone Lake, to twice that amount at higher elevations.[147]

The climate at Yellowstone Lake is classified as subarctic (Dfc), according to Köppen-Geiger climate classification, while at the park headquarters, the classification is humid continental (Dfb).

Tornadoes in Yellowstone are rare; however, on July 21, 1987, the most powerful tornado recorded in Wyoming touched down in the Teton Wilderness of Bridger-Teton National Forest and hit Yellowstone National Park. Called the Teton–Yellowstone tornado, it was classified as an F4, with wind speeds estimated at between 207 and 260 miles per hour (333 and 418 km/h). The tornado left a path of destruction 1 to 2 miles (1.6 to 3.2 km) wide, and 24 miles (39 km) long, and leveled 15,000 acres (6,100 ha; 23 sq mi) of mature pine forest.[148]

In June 2022, the park closed entrances and evacuated visitors after experiencing record-level rainfall and flooding that caused multiple road and bridge failures, power outages, and mudslides.[149] A combination of heavy rain and rapid snow melt resulted in the Yellowstone River rising to a new record height at 13.88 feet (4.23 m), breaking a previous record of 11.5 feet (3.5 m) set in 1918.[150] Flooding on the Lamar River reached 16.7 feet (5.1 m), beating a 1996 record of 12.15 feet (3.70 m).[151] Damage from the flooding includes washed out roads and bridges, and damage to infrastructure systems including electricity, water and wastewater systems. It's unlikely that the park will be able to reopen the north entrance by Gardiner, MT, or the northeast entrance near Cooke City, MT, during the 2022 season.[152] The park partially reopened Wednesday, June 22, after a 9-day closure. To limit the nearly one million visitors per month that visit in the summer, the park has restricted entry to cars based on license plates. Cars with license plates ending in even numbers can enter on even-numbered dates, and plates ending in odd numbers can enter on odd-numbered dates.[153]

Climate data for Yellowstone Lake, 1991–2020 normals, extremes 1904–present
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Record high °F (°C) 48
(9)
49
(9)
60
(16)
73
(23)
78
(26)
84
(29)
92
(33)
91
(33)
89
(32)
76
(24)
63
(17)
52
(11)
92
(33)
Mean maximum °F (°C) 37.2
(2.9)
40.7
(4.8)
49.9
(9.9)
56.3
(13.5)
66.6
(19.2)
75.6
(24.2)
81.2
(27.3)
81.1
(27.3)
76.4
(24.7)
64.6
(18.1)
49.0
(9.4)
37.3
(2.9)
82.7
(28.2)
Average high °F (°C) 23.2
(−4.9)
26.7
(−2.9)
35.0
(1.7)
41.5
(5.3)
50.4
(10.2)
60.8
(16.0)
71.2
(21.8)
70.9
(21.6)
61.4
(16.3)
46.0
(7.8)
32.6
(0.3)
23.6
(−4.7)
45.3
(7.4)
Daily mean °F (°C) 13.3
(−10.4)
15.1
(−9.4)
22.9
(−5.1)
30.4
(−0.9)
39.7
(4.3)
48.5
(9.2)
56.9
(13.8)
56.2
(13.4)
47.7
(8.7)
35.6
(2.0)
23.7
(−4.6)
15.4
(−9.2)
33.8
(1.0)
Average low °F (°C) 3.3
(−15.9)
3.5
(−15.8)
10.8
(−11.8)
19.3
(−7.1)
29.0
(−1.7)
36.3
(2.4)
42.7
(5.9)
41.6
(5.3)
34.1
(1.2)
25.2
(−3.8)
14.8
(−9.6)
7.2
(−13.8)
22.3
(−5.4)
Mean minimum °F (°C) −21.2
(−29.6)
−23.2
(−30.7)
−13.4
(−25.2)
−0.6
(−18.1)
12.2
(−11.0)
25.0
(−3.9)
31.7
(−0.2)
29.4
(−1.4)
21.5
(−5.8)
6.8
(−14.0)
−7.1
(−21.7)
−14.6
(−25.9)
−28.1
(−33.4)
Record low °F (°C) −51
(−46)
−56
(−49)
−43
(−42)
−29
(−34)
−10
(−23)
14
(−10)
20
(−7)
13
(−11)
−5
(−21)
−17
(−27)
−30
(−34)
−48
(−44)
−56
(−49)
Average precipitation inches (mm) 1.97
(50)
1.80
(46)
1.97
(50)
2.12
(54)
2.42
(61)
2.46
(62)
1.29
(33)
1.49
(38)
1.58
(40)
1.64
(42)
1.81
(46)
1.99
(51)
22.54
(573)
Average snowfall inches (cm) 35.8
(91)
30.9
(78)
25.1
(64)
22.9
(58)
6.9
(18)
1.0
(2.5)
0.0
(0.0)
0.0
(0.0)
1.4
(3.6)
10.2
(26)
29.8
(76)
35.4
(90)
199.4
(507.1)
Average precipitation days (≥ 0.01 in) 17.2 15.1 13.9 12.3 11.3 13.4 9.9 10.4 9.7 9.2 12.3 16.5 151.2
Average snowy days (≥ 0.1 in) 16.3 14.4 12.3 10.2 4.3 0.8 0.0 0.0 0.8 5.5 11.8 15.4 91.8
Source 1: NOAA[154]
Source 2: National Weather Service[155]
Climate data for Yellowstone National Park – Mammoth, Wyoming, 1991–2020 normals, extremes 1894–present
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Record high °F (°C) 53
(12)
56
(13)
66
(19)
78
(26)
86
(30)
92
(33)
99
(37)
97
(36)
92
(33)
81
(27)
66
(19)
57
(14)
99
(37)
Mean maximum °F (°C) 44.6
(7.0)
47.8
(8.8)
57.1
(13.9)
68.0
(20.0)
76.9
(24.9)
85.2
(29.6)
91.2
(32.9)
90.5
(32.5)
85.4
(29.7)
73.0
(22.8)
56.8
(13.8)
44.8
(7.1)
92.3
(33.5)
Average high °F (°C) 31.4
(−0.3)
34.2
(1.2)
41.9
(5.5)
49.7
(9.8)
59.6
(15.3)
69.5
(20.8)
80.8
(27.1)
79.8
(26.6)
68.8
(20.4)
53.6
(12.0)
39.4
(4.1)
30.3
(−0.9)
53.3
(11.8)
Daily mean °F (°C) 21.7
(−5.7)
23.3
(−4.8)
30.5
(−0.8)
38.0
(3.3)
47.1
(8.4)
55.8
(13.2)
64.6
(18.1)
63.1
(17.3)
53.9
(12.2)
41.3
(5.2)
29.3
(−1.5)
21.1
(−6.1)
40.8
(4.9)
Average low °F (°C) 11.9
(−11.2)
12.3
(−10.9)
19.1
(−7.2)
26.3
(−3.2)
34.6
(1.4)
42.0
(5.6)
48.3
(9.1)
46.5
(8.1)
39.0
(3.9)
28.9
(−1.7)
19.2
(−7.1)
11.9
(−11.2)
28.3
(−2.1)
Mean minimum °F (°C) −9.5
(−23.1)
−8.7
(−22.6)
0.8
(−17.3)
12.1
(−11.1)
22.6
(−5.2)
32.2
(0.1)
40.0
(4.4)
36.9
(2.7)
27.7
(−2.4)
12.6
(−10.8)
−0.2
(−17.9)
−9.1
(−22.8)
−18.0
(−27.8)
Record low °F (°C) −36
(−38)
−35
(−37)
−24
(−31)
−6
(−21)
6
(−14)
20
(−7)
21
(−6)
24
(−4)
0
(−18)
−8
(−22)
−27
(−33)
−35
(−37)
−36
(−38)
Average precipitation inches (mm) 0.91
(23)
0.79
(20)
1.09
(28)
1.40
(36)
1.82
(46)
1.86
(47)
1.27
(32)
1.05
(27)
1.21
(31)
1.34
(34)
1.15
(29)
0.91
(23)
14.80
(376)
Average snowfall inches (cm) 11.5
(29)
11.5
(29)
10.9
(28)
7.8
(20)
1.7
(4.3)
0.3
(0.76)
0.0
(0.0)
0.0
(0.0)
0.6
(1.5)
4.7
(12)
9.9
(25)
12.6
(32)
71.5
(182)
Average precipitation days (≥ 0.01 in) 10.6 11.4 10.5 11.3 12.8 12.5 9.2 8.5 8.7 9.7 9.6 11.9 126.7
Average snowy days (≥ 0.1 in) 8.7 9.4 7.0 5.5 1.2 0.1 0.0 0.0 0.3 2.8 7.5 10.2 52.7
Source: NOAA[156][157]

Recreation

 
Union Pacific Railroad brochure promoting travel to the park (1921)

Yellowstone ranks among the most popular national parks in the United States. Since the mid-1960s, at least 2 million tourists have visited the park almost every year.[158] Average annual visitation increased to 3.5 million during the ten years from 2007 to 2016, with a record of 4,257,177 recreational visitors in 2016.[159] July is the busiest month for Yellowstone National Park.[160] At peak summer levels, 3,700 employees work for Yellowstone National Park concessionaires. Concessionaires manage nine hotels and lodges, with a total of 2,238 hotel rooms and cabins available. They also oversee gas stations, stores, and most of the campgrounds. Another 800 employees work either permanently or seasonally for the National Park Service.[11]

 
Tourists watch Old Faithful erupt, 2019.

Park service roads lead to major features; however, road reconstruction has produced temporary road closures. Yellowstone is in the midst of a long-term road reconstruction effort, which is hampered by a short repair season. In the winter, all roads aside from the one which enters from Gardiner, Montana, and extends to Cooke City, Montana, are closed to wheeled vehicles.[161] Park roads are closed to wheeled vehicles from early November to mid-April, but some park roads remain closed until mid-May.[162] The park has 310 miles (500 km) of paved roads which can be accessed from five different entrances.[11] There is no public transportation available inside the park, but several tour companies can be contacted for guided (including self-guided) motorized transport. In the winter, concessionaires operate guided snowmobile and snow coach tours, though their numbers and access are based on quotas established by the National Park Service.[163] Facilities in the Old Faithful, Canyon and Mammoth Hot Springs areas of the park are very busy during the summer months. Traffic jams created by road construction or by people observing wildlife can result in long delays.

The National Park Service maintains nine visitor centers and museums and is responsible for the maintenance of historical structures and many of the other 2,000 buildings. These structures include National Historical Landmarks such as the Old Faithful Inn built from 1903 to 1904 and the entire Fort Yellowstone – Mammoth Hot Springs Historic District. A historical and educational tour is available at Fort Yellowstone which details the history of the National Park Service and the development of the park. Campfire programs, guided walks, and other interpretive presentations normally available at numerous locations in the summer, and on a limited basis during other seasons were suspended in 2021 as a COVID-19 response.[164]

Camping is available at a dozen campgrounds with more than 2,000 campsites.[11] Camping is also available in surrounding National Forests, as well as in Grand Teton National Park to the south. Backcountry campsites are accessible only by foot or by horseback and require a permit. There are 1,100 miles (1,800 km) of hiking trails available.[165] The park is not considered to be a good destination for mountaineering because of the instability of volcanic rock which predominates. Visitors with pets are required to keep them on a leash at all times and are limited to areas near roadways and in "front country" zones such as drive-in campgrounds.[166] Around thermal features, wooden and paved trails have been constructed to ensure visitor safety, and most of these areas are handicapped accessible. The National Park Service maintains a year-round clinic at Mammoth Hot Springs and provides emergency services throughout the year.[167]

Hunting is not permitted, though it is allowed in the surrounding national forests during the open season. Fishing is a popular activity, and a Yellowstone Park fishing license is required to fish in park waters.[168] Many park waters are fly fishing only and all native fish species are catch and release only.[169] Boating is prohibited on rivers and creeks except for a 5 miles (8.0 km) stretch of the Lewis River between Lewis and Shoshone lakes, and it is open to non-motorized use only. Yellowstone Lake has a marina at Bridge Bay while there is a boat ramp at the Lewis lake campground.[170]

 
Vintage photo of human-habituated bears seeking food from visitors

In the early history of the park, visitors were allowed, and sometimes even encouraged, to feed the bears. Visitors welcomed the chance to get their pictures taken with the bears, who had learned to beg for food. This led to numerous injuries to humans each year. In 1970, park officials changed their policy and started a vigorous program to educate the public on the dangers of close contact with bears, and to try to eliminate opportunities for bears to find food in campgrounds and trash collection areas. Although it has become more difficult to observe bears in recent years, the number of human injuries and deaths has taken a significant drop and visitors are in less danger.[171] The eighth recorded bear-related death in the park's history occurred in August 2015.[172]

Other protected lands in the region include Caribou-Targhee, Gallatin, Custer, Shoshone and Bridger-Teton National Forests. The National Park Service's John D. Rockefeller, Jr. Memorial Parkway is to the south and leads to Grand Teton National Park. The famed Beartooth Highway provides access from the northeast and has spectacular high-altitude scenery. Nearby communities include West Yellowstone, Montana; Cody, Wyoming; Red Lodge, Montana; Ashton, Idaho; and Gardiner, Montana. The closest air transport is available by way of Bozeman, Montana; Billings, Montana; Jackson; Cody, Wyoming, or Idaho Falls, Idaho.[173] Salt Lake City, 320 miles (510 km) to the south, is the closest large metropolitan area.

Legal jurisdiction

 
Idaho portion of park highlighted in southwest corner (click to enlarge)

The entire park is within the jurisdiction of the United States District Court for the District of Wyoming, making it the only federal court district that includes portions of more than one state (Idaho, Montana, and Wyoming). Law professor Brian C. Kalt has argued that it may be impossible to impanel a jury in compliance with the Vicinage Clause of the Sixth Amendment for a crime committed solely in the unpopulated Idaho portion of the park (and that it would be difficult to do so for a crime committed solely in the lightly populated Montana portion).[174] One defendant, who was accused of a wildlife-related crime in the Montana portion of the park, attempted to raise this argument but eventually pleaded guilty, with the plea deal including his specific agreement not to raise the issue in his appeal.[175][176][177]

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Further reading

  • Whittlesey, Lee H. (2002), "Native Americans, the Earliest Interpreters: What is Known About Their Legends and Stories of Yellowstone National Park and the Complexities of Interpreting Them", The George Wright Forum, published by the George Wright Society, Vol. 19, No. 3, pp. 40–51. JSTOR 43598916.

External links

  • Official website   of the National Park Service
  • Travertine: Yellowstone’s Hydrothermal Timekeeper USGS May 24, 2021
  • Act Establishing Yellowstone National Park from the Library of Congress
  • Congressional Acts Pertaining to Yellowstone
  • The Yellowstone magmatic system from the mantle plume to the upper crust at Science (registration required)
  • BYU Larsen Yellowstone collection at the L. Tom Perry Special Collections Library of Brigham Young University
  • Yellowstone articles, photos and videos at National Geographic
  • Photographic library of the U.S. Geological Survey ()
  • The short film A Visit to Yellowstone National Park (c. 1932) is available for free download at the Internet Archive.
  • The short film Four Seasons of Yellowstone (1970) is available for free download at the Internet Archive.
  • The short film Fantastic Yellowstone (1997) is available for free download at the Internet Archive.
  • Historic American Engineering Record (HAER) documentation:
    • HAER No. MT-91, "West Entrance Road, West Yellowstone, Gallatin County, MT", 11 data pages
    • HAER No. MT-92, "Gallatin Entrance Road, West Yellowstone, Gallatin County, MT", 15 data pages
    • HAER No. MT-93, "North Entrance Road, Gardiner, Park County, MT", 1 color transparency, 10 data pages, 1 photo caption page

yellowstone, national, park, yellowstone, redirects, here, other, uses, yellowstone, disambiguation, american, national, park, located, western, united, states, largely, northwest, corner, wyoming, extending, into, montana, idaho, established, 42nd, congress, . Yellowstone redirects here For other uses see Yellowstone disambiguation Yellowstone National Park is an American national park located in the western United States largely in the northwest corner of Wyoming and extending into Montana and Idaho It was established by the 42nd U S Congress with the Yellowstone National Park Protection Act and signed into law by President Ulysses S Grant on March 1 1872 6 7 8 9 Yellowstone was the first national park in the U S and is also widely held to be the first national park in the world 10 The park is known for its wildlife and its many geothermal features especially the Old Faithful geyser one of its most popular 11 While it represents many types of biomes the subalpine forest is the most abundant It is part of the South Central Rockies forests ecoregion Yellowstone National ParkIUCN category II national park 1 Grand Canyon of the YellowstoneLocation of Yellowstone National ParkShow map of WyomingYellowstone National Park the United States Show map of the United StatesLocationUnited States Park County Wyoming Teton County Wyoming Gallatin County Montana Park County Montana Fremont County IdahoNearest townWest Yellowstone MontanaCoordinates44 35 47 N 110 32 50 W 44 59639 N 110 54722 W 44 59639 110 54722 Coordinates 44 35 47 N 110 32 50 W 44 59639 N 110 54722 W 44 59639 110 54722 2 Area2 219 791 acres 8 983 18 km2 3 Elevation8 104 ft 2 470 m EstablishedMarch 1 1872 151 years ago 1872 03 01 Visitors3 806 306 in 2020 4 Governing bodyU S National Park ServiceWebsitewww wbr nps wbr gov wbr yell wbr UNESCO World Heritage SiteTypeNaturalCriteriavii viii ix xDesignated1978 2nd session Reference no 28 5 RegionThe AmericasEndangered1995 2003While Native Americans have lived in the Yellowstone region for at least 11 000 years 12 aside from visits by mountain men during the early to mid 19th century organized exploration did not begin until the late 1860s Management and control of the park originally fell under the jurisdiction of the United States Department of the Interior the first Secretary of the Interior to supervise the park being Columbus Delano However the U S Army was eventually commissioned to oversee the management of Yellowstone for 30 years between 1886 and 1916 13 In 1917 administration of the park was transferred to the National Park Service which had been created the previous year Hundreds of structures have been built and are protected for their architectural and historical significance and researchers have examined more than a thousand archaeological sites Yellowstone National Park spans an area of 3 468 4 sq mi 8 983 km2 3 comprising lakes canyons rivers and mountain ranges 11 Yellowstone Lake is one of the largest high elevation lakes in North America and is centered over the Yellowstone Caldera the largest supervolcano on the continent The caldera is considered a dormant volcano It has erupted with tremendous force several times in the last two million years 14 Well over half of the world s geysers 15 16 and hydrothermal features 17 are in Yellowstone fueled by this ongoing volcanism Lava flows and rocks from volcanic eruptions cover most of the land area of Yellowstone The park is the centerpiece of the Greater Yellowstone Ecosystem the largest remaining nearly intact ecosystem in the Earth s northern temperate zone 18 In 1978 Yellowstone was named a UNESCO World Heritage Site Hundreds of species of mammals birds fish reptiles and amphibians have been documented including several that are either endangered or threatened 11 The vast forests and grasslands also include unique species of plants Yellowstone Park is the largest and most famous megafauna location in the contiguous United States Grizzly bears wolves and free ranging herds of bison and elk live in this park The Yellowstone Park bison herd is the oldest and largest public bison herd in the United States Forest fires occur in the park each year in the large forest fires of 1988 nearly one third of the park was burnt Yellowstone has numerous recreational opportunities including hiking camping boating fishing and sightseeing Paved roads provide close access to the major geothermal areas as well as some of the lakes and waterfalls During the winter visitors often access the park by way of guided tours that use either snow coaches or snowmobiles 19 Contents 1 History 1 1 Park creation 1 2 Later history 1 3 Heritage and Research Center 2 Geography 3 Geology 3 1 Volcanism 3 2 Geysers and the hydrothermal system 3 3 Earthquakes 4 Biology and ecology 4 1 Flora 4 2 Fauna 5 Forest fires 6 Climate and weather 7 Recreation 8 Legal jurisdiction 9 See also 10 References 11 Further reading 12 External linksHistory EditThe park contains the headwaters of the Yellowstone River from which it takes its historical name Near the end of the 18th century French trappers named the river Roche Jaune which is probably a translation of the Hidatsa name Mi tsi a da zi Yellow Stone River 20 Later American trappers rendered the French name in English as Yellow Stone Although it is commonly believed that the river was named for the yellow rocks seen in the Grand Canyon of the Yellowstone the Native American name source is unclear 21 Detailed pictorial map from 1904 The human history of the park began at least 11 000 years ago when Native Americans began to hunt and fish in the region During the construction of the post office in Gardiner Montana in the 1950s an obsidian point of Clovis origin was found that dated from approximately 11 000 years ago 22 These Paleo Indians of the Clovis culture used the significant amounts of obsidian found in the park to make cutting tools and weapons Arrowheads made of Yellowstone obsidian have been found as far away as the Mississippi Valley indicating that a regular obsidian trade existed between local tribes and tribes farther east 23 When the Lewis and Clark Expedition entered present day Montana in 1805 they encountered the Nez Perce Crow and Shoshone tribes who described to them the Yellowstone region to the south but they chose not to investigate 24 In 1806 John Colter a member of the Lewis and Clark Expedition left to join a group of fur trappers After splitting up with the other trappers in 1807 Colter passed through a portion of what later became the park during the winter of 1807 1808 He observed at least one geothermal area in the northeastern section of the park near Tower Fall 25 After surviving wounds he suffered in a battle with members of the Crow and Blackfoot tribes in 1809 Colter described a place of fire and brimstone that most people dismissed as delirium the supposedly mystical place was nicknamed Colter s Hell Over the next 40 years numerous reports from mountain men and trappers told of boiling mud steaming rivers and petrified trees yet most of these reports were believed at the time to be a myth 26 After an 1856 exploration mountain man Jim Bridger also believed to be the first or second European American to have seen the Great Salt Lake reported observing boiling springs spouting water and a mountain of glass and yellow rock These reports were largely ignored because Bridger was a known spinner of yarns In 1859 a U S Army Surveyor named Captain William F Raynolds embarked on a two year survey of the southern central Rockies After wintering in Wyoming in May 1860 Raynolds and his party which included geologist Ferdinand V Hayden and guide Jim Bridger attempted to cross the Continental Divide over Two Ocean Plateau from the Wind River drainage in northwest Wyoming Heavy spring snows prevented their passage but had they been able to traverse the divide the party would have been the first organized survey to enter the Yellowstone region 27 The American Civil War hampered further organized explorations until the late 1860s 28 Ferdinand V Hayden 1829 1887 an American geologist who convinced Congress to make Yellowstone a national park in 1872 The first detailed expedition to the Yellowstone area was the Cook Folsom Peterson Expedition of 1869 which consisted of three privately funded explorers The Folsom party followed the Yellowstone River to Yellowstone Lake 29 The members of the Folsom party kept a journal and based on the information it reported a party of Montana residents organized the Washburn Langford Doane Expedition in 1870 It was headed by the surveyor general of Montana Henry Washburn and included Nathaniel P Langford who later became known as National Park Langford and a U S Army detachment commanded by Lt Gustavus Doane The expedition spent about a month exploring the region collecting specimens and naming sites of interest 30 A Montana writer and lawyer named Cornelius Hedges who had been a member of the Washburn expedition proposed that the region should be set aside and protected as a national park he wrote detailed articles about his observations for the Helena Herald newspaper between 1870 and 1871 Hedges essentially restated comments made in October 1865 by acting Montana Territorial Governor Thomas Francis Meagher who had previously commented that the region should be protected 31 Others made similar suggestions An 1871 letter to Ferdinand V Hayden from Jay Cooke a businessman who wanted to bring tourists to the region encouraged him to mention it in his official report of the survey 32 Cooke wrote that his friend Congressman William D Kelley had also suggested Congress pass a bill reserving the Great Geyser Basin as a public park forever 33 Park creation Edit See also Expeditions and the protection of Yellowstone 1869 1890 Presidency of Ulysses S Grant and Columbus Delano Ferdinand V Hayden s map of Yellowstone National Park 1871 In 1871 eleven years after his failed first effort Ferdinand V Hayden was finally able to explore the region With government sponsorship he returned to the region with a second larger expedition the Hayden Geological Survey of 1871 He compiled a comprehensive report including large format photographs by William Henry Jackson and paintings by Thomas Moran The report helped to convince the U S Congress to withdraw this region from public auction On March 1 1872 President Ulysses S Grant signed The Act of Dedication 8 law that created Yellowstone National Park 34 Hayden while not the only person to have thought of creating a park in the region was its first and most enthusiastic advocate 35 He believed in setting aside the area as a pleasure ground for the benefit and enjoyment of the people and warned that there were those who would come and make merchandise of these beautiful specimens 35 Worrying the area could face the same fate as Niagara Falls he concluded the site should be as free as the air or Water 35 In his report to the Committee on Public Lands he concluded that if the bill failed to become law the vandals who are now waiting to enter into this wonder land will in a single season despoil beyond recovery these remarkable curiosities which have required all the cunning skill of nature thousands of years to prepare 36 37 Hayden and his 1871 party recognized Yellowstone as a unique place that should be available for further research He also was encouraged to preserve it for others to see and experience it as well In 1873 Congress authorized and funded a survey to find a wagon route to the park from the south which was completed by the Jones Expedition of 1873 38 Eventually the railroads and sometime after that the automobile would make that possible The park was not set aside strictly for ecological purposes however the designation pleasure ground was not an invitation to create an amusement park Hayden imagined something akin to the scenic resorts and baths in England Germany and Switzerland 35 THE ACT OF DEDICATION 37 AN ACT to set apart a certain tract of land lying near the headwaters of the Yellowstone River as a public park Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled That the tract of land in the Territories of Montana and Wyoming is hereby reserved and withdrawn from settlement occupancy or sale under the laws of the United States and dedicated and set apart as a public park or pleasuring ground for the benefit and enjoyment of the people and all persons who shall locate or settle upon or occupy the same or any part thereof except as hereinafter provided shall be considered trespassers and removed there from Approved March 1 1872 Signed by ULYSSES S GRANT President of the United States SCHUYLER COLFAX Vice President of the United States and President of the Senate JAMES G BLAINE Speaker of the House Portrait of Nathaniel P Langford 1870 the first superintendent of the park 39 There was considerable local opposition to Yellowstone National Park during its early years Some of the locals feared that the regional economy would be unable to thrive if there remained strict federal prohibitions against resource development or settlement within park boundaries and local entrepreneurs advocated reducing the size of the park so that mining hunting and logging activities could be developed 40 To this end numerous bills were introduced into Congress by Montana representatives who sought to remove the federal land use restrictions 41 After the park s official formation Nathaniel Langford was appointed as the park s first superintendent in 1872 by the Secretary of Interior Columbus Delano the first overseer and controller of the park 42 Langford served for five years but was denied a salary funding and staff Langford lacked the means to improve the land or properly protect the park and without formal policy or regulations he had few legal methods to enforce such protection This left Yellowstone vulnerable to poachers vandals and others seeking to raid its resources He addressed the practical problems park administrators faced in the 1872 Report to the Secretary of the Interior 43 and correctly predicted that Yellowstone would become a major international attraction deserving the continuing stewardship of the government In 1874 both Langford and Delano advocated the creation of a federal agency to protect the vast park but Congress refused In 1875 Colonel William Ludlow who had previously explored areas of Montana under the command of George Armstrong Custer was assigned to organize and lead an expedition to Montana and the newly established Yellowstone Park Observations about the lawlessness and exploitation of park resources were included in Ludlow s Report of a Reconnaissance to the Yellowstone National Park The report included letters and attachments by other expedition members including naturalist and mineralogist George Bird Grinnell 44 Great Falls of the Yellowstone U S Geological and Geographic Survey of the Territories 1874 1879 photographer William Henry Jackson Grinnell documented the poaching of buffalo deer elk and antelope for hides It is estimated that during the winter of 1874 1875 not less than 3 000 buffalo and mule deer suffer even more severely than the elk and the antelope nearly as much 45 As a result Langford was forced to step down in 1877 46 47 Having traveled through Yellowstone and witnessed land management problems Philetus Norris volunteered for the position following Langford s exit Congress finally saw fit to implement a salary for the position as well as to provide minimal funding to operate the park Norris used these funds to expand access to the park building numerous crude roads and facilities 47 In 1880 Harry Yount was appointed as a gamekeeper to control poaching and vandalism in the park Yount had previously spent decades exploring the mountain country of present day Wyoming including the Grand Tetons after joining F V Hayden s Geological Survey in 1873 48 Yount is the first national park ranger 49 and Yount s Peak at the head of the Yellowstone River was named in his honor 50 However these measures still proved to be insufficient in protecting the park as neither Norris nor the three superintendents who followed were given sufficient manpower or resources The Northern Pacific Railroad built a train station in Livingston Montana connecting to the northern entrance in the early 1880s which helped to increase visitation from 300 in 1872 to 5 000 in 1883 51 A line was also extended from Livingston to Gardiner station where passengers switched to stagecoach 52 Visitors in these early years faced poor roads and limited services and most access into the park was on horse or via stagecoach By 1908 visitation increased enough to attract a Union Pacific Railroad connection to West Yellowstone though rail visitation fell off considerably by World War II and ceased around the 1960s Left Thomas Moran painted Tower Creek while on the Hayden Geological Survey of 1871 Right Travertine Terrace Mammoth Hot Springs During the 1870s and 1880s Native American tribes were effectively excluded from the national park Under a half dozen tribes had made seasonal use of the Yellowstone area the only year round residents were small bands of Eastern Shoshone known as Sheepeaters They left the area under the assurances of a treaty negotiated in 1868 under which the Sheepeaters ceded their lands but retained the right to hunt in Yellowstone The United States never ratified the treaty and refused to recognize the claims of the Sheepeaters or any other tribe that had used Yellowstone 53 The Nez Perce band associated with Chief Joseph numbering about 750 people passed through Yellowstone National Park in thirteen days in late August 1877 They were being pursued by the U S Army and entered the national park about two weeks after the Battle of the Big Hole Some of the Nez Perce were friendly to the tourists and other people they encountered in the park some were not Nine park visitors were briefly taken captive Despite Joseph and other chiefs ordering that no one should be harmed at least two people were killed and several wounded 54 55 One of the areas where encounters occurred was in Lower Geyser Basin and east along a branch of the Firehole River to Mary Mountain and beyond 54 That stream is still known as Nez Perce Creek 56 A group of Bannocks entered the park in 1878 alarming park Superintendent Philetus Norris In the aftermath of the Sheepeater Indian War of 1879 Norris built a fort to prevent Native Americans from entering the national park 53 55 Fort Yellowstone circa 1910 formerly a U S Army post now serves as park headquarters Ongoing poaching and destruction of natural resources continued unabated until the U S Army arrived at Mammoth Hot Springs in 1886 and built Camp Sheridan Over the next 22 years as the army constructed permanent structures Camp Sheridan was renamed Fort Yellowstone 57 On May 7 1894 the Boone and Crockett Club acting through the personality of George G Vest Arnold Hague William Hallett Phillips W A Wadsworth Archibald Rogers Theodore Roosevelt and George Bird Grinnell were successful in carrying through the Park Protection Act which saved the park 58 The Lacey Act of 1900 provided legal support for the officials prosecuting poachers With the funding and manpower necessary to keep a diligent watch the army developed its own policies and regulations that permitted public access while protecting park wildlife and natural resources When the National Park Service was created in 1916 many of the management principles developed by the army were adopted by the new agency 57 The army turned control over to the National Park Service on October 31 1918 59 In 1898 the naturalist John Muir described the park as follows However orderly your excursions or aimless again and again amid the calmest stillest scenery you will be brought to a standstill hushed and awe stricken before phenomena wholly new to you Boiling springs and huge deep pools of purest green and azure water thousands of them are plashing and heaving in these high cool mountains as if a fierce furnace fire were burning beneath each one of them and a hundred geysers white torrents of boiling water and steam like inverted waterfalls are ever and anon rushing up out of the hot black underworld 60 Later history Edit Superintendent Horace M Albright and black bears 1922 Tourists often fed black bears in the park s early years with 527 injuries reported from 1931 to 1939 61 By 1915 1 000 automobiles per year were entering the park resulting in conflicts with horses and horse drawn transportation Horse travel on roads was eventually prohibited 62 The Civilian Conservation Corps CCC a New Deal relief agency for young men played a major role between 1933 and 1942 in developing Yellowstone facilities CCC projects included reforestation campground development of many of the park s trails and campgrounds trail construction fire hazard reduction and fire fighting work The CCC built the majority of the early visitor centers campgrounds and the current system of park roads 63 During World War II tourist travel fell sharply staffing was cut and many facilities fell into disrepair 64 By the 1950s visitation increased tremendously in Yellowstone and other national parks To accommodate the increased visitation park officials implemented Mission 66 an effort to modernize and expand park service facilities Planned to be completed by 1966 in honor of the 50th anniversary of the founding of the National Park Service Mission 66 construction diverged from the traditional log cabin style with design features of a modern style 65 During the late 1980s most construction styles in Yellowstone reverted to the more traditional designs After the enormous forest fires of 1988 damaged much of Grant Village structures there were rebuilt in the traditional style The visitor center at Canyon Village which opened in 2006 incorporates a more traditional design as well 66 The Roosevelt Arch in Gardiner Montana at the north entrance The 1959 Hebgen Lake earthquake just west of Yellowstone at Hebgen Lake damaged roads and some structures in the park In the northwest section of the park new geysers were found and many existing hot springs became turbid 67 It was the most powerful earthquake to hit the region in recorded history In 1963 after several years of public controversy regarding the forced reduction of the elk population in Yellowstone the United States Secretary of the Interior Stewart Udall appointed an advisory board to collect scientific data to inform future wildlife management of the national parks In a paper known as the Leopold Report the committee observed that culling programs at other national parks had been ineffective and recommended the management of Yellowstone s elk population 68 The wildfires during the summer of 1988 were the largest in the history of the park Approximately 793 880 acres 3 210 km2 1 240 sq mi or 36 of the parkland was impacted by the fires leading to a systematic re evaluation of fire management policies The fire season of 1988 was considered normal until a combination of drought and heat by mid July contributed to an extreme fire danger On Black Saturday August 20 1988 strong winds expanded the fires rapidly and more than 150 000 acres 610 km2 230 sq mi burned 69 Pictorial map by Heinrich C Berann 1991 scale exaggerated The expansive cultural history of the park has been documented by the 1 000 archeological sites that have been discovered The park has 1 106 historic structures and features and of these Obsidian Cliff and five buildings have been designated National Historic Landmarks 11 Yellowstone was designated an International Biosphere Reserve on October 26 1976 and a UN World Heritage Site on September 8 1978 The park was placed on the List of World Heritage in Danger from 1995 to 2003 due to the effects of tourism infection of wildlife and issues with invasive species 70 In 2010 Yellowstone National Park was honored with its own quarter under the America the Beautiful Quarters Program 71 Justin Ferrell explores three moral sensibilities that motivated activists in dealing with Yellowstone First came the utilitarian vision of maximum exploitation of natural resources a characteristic of developers in the late 19th century Second was the spiritual vision of nature inspired by Romanticism and the transcendentalists in the mid 19th century The twentieth century saw the biocentric moral vision that focuses on the health of the ecosystem as theorized by Aldo Leopold which led to the expansion of federally protected areas and the surrounding ecosystems 72 Heritage and Research Center Edit The Heritage and Research Center is located at Gardiner Montana near the north entrance to the park 73 The center is home to the Yellowstone National Park s museum collection archives research library historian archeology lab and herbarium The Yellowstone National Park Archives maintain collections of historical records of Yellowstone and the National Park Service The collection includes the administrative records of Yellowstone as well as resource management records records from major projects and donated manuscripts and personal papers The archives are affiliated with the National Archives and Records Administration 74 75 Geography EditSee also Mountains and mountain ranges of Yellowstone National Park Waterfalls in Yellowstone National Park and Plateaus of Yellowstone National Park Official park map c 2020 click on map to enlarge Satellite image of Yellowstone National Park in 2020 Interactive map of Yellowstone National Park Approximately 96 percent of the land area of Yellowstone National Park is located within the state of Wyoming 11 Another three percent is within Montana with the remaining one percent in Idaho The park is 63 miles 101 km north to south and 54 miles 87 km west to east by air Yellowstone is 2 219 789 acres 8 983 km2 3 468 sq mi 3 in area larger than either of the states of Rhode Island or Delaware Rivers and lakes cover five percent of the land area with the largest water body being Yellowstone Lake at 87 040 acres 352 km2 136 sq mi Yellowstone Lake is up to 400 feet 120 m deep and has 110 miles 180 km of shoreline At an elevation of 7 733 feet 2 357 m above sea level Yellowstone Lake is the largest high elevation lake in North America Forests comprise 80 percent of the land area of the park most of the rest is grassland 11 The Continental Divide of North America runs diagonally through the southwestern part of the park The divide is a topographic feature that separates the Pacific Ocean and Atlantic Ocean water drainages About one third of the park lies on the west side of the divide The origins of the Yellowstone and Snake Rivers are near each other but on opposite sides of the divide As a result the waters of the Snake River flow to the Pacific Ocean while those of the Yellowstone find their way to the Gulf of Mexico 76 The park sits on the Yellowstone Plateau at an average elevation of 8 000 feet 2 400 m above sea level The plateau is bounded on nearly all sides by mountain ranges of the Middle Rocky Mountains which range from 9 000 to 11 000 feet 2 700 to 3 400 m in elevation The highest point in the park is atop Eagle Peak 11 358 feet or 3 462 metres and the lowest is along Reese Creek 5 282 feet or 1 610 metres 11 Nearby mountain ranges include the Gallatin Range to the northwest the Beartooth Mountains in the north the Absaroka Range to the east the Teton Range to the south and the Madison Range to the west The most prominent summit on the Yellowstone Plateau is Mount Washburn at 10 243 feet 3 122 m 77 Yellowstone National Park has one of the world s largest petrified forests trees which were long ago buried by ash and soil and transformed from wood to mineral materials This ash and other volcanic debris are believed to have come from the park area itself as the central part of Yellowstone is the massive caldera of a supervolcano The park contains 290 waterfalls of at least 15 feet 4 6 m the highest being the Lower Falls of the Yellowstone River at 308 feet 94 m 11 Three deep canyons are located in the park cut through the volcanic tuff of the Yellowstone Plateau by rivers over the last 640 000 years The Lewis River flows through Lewis Canyon in the south and the Yellowstone River has carved two colorful canyons the Grand Canyon of the Yellowstone and the Black Canyon of the Yellowstone in its journey north 77 78 79 Geology EditMain articles Geothermal areas of Yellowstone Yellowstone Caldera and Yellowstone hotspot Volcanism Edit Columnar basalt near Tower Fall large floods of basalt and other lava types preceded mega eruptions of superheated ash and pumice Caldera rim on the horizon south of Yellowstone Lake Yellowstone is at the northeastern end of the Snake River Plain a great U shaped arc through the mountains that extends from Boise Idaho some 400 miles 640 km to the west The volcanism of Yellowstone is believed to be linked to the somewhat older volcanism of the Snake River plain Yellowstone is thus the active part of a hotspot that has moved northeast over time 80 The origin of this hotspot volcanism is disputed 81 One theory holds that a mantle plume has caused the Yellowstone hotspot to migrate northeast while another theory explains migrating hotspot volcanism as the result of the fragmentation and dynamics of the subducted Farallon Plate in Earth s interior 81 82 The Yellowstone Caldera is the largest volcanic system in North America and worldwide it is only rivaled by the Lake Toba Caldera on Sumatra It has been termed a supervolcano because the caldera was formed by exceptionally large explosive eruptions The magma chamber that lies under Yellowstone is estimated to be a single connected chamber about 37 miles 60 km long 18 miles 29 km wide and 3 to 7 miles 5 to 12 km deep 83 The current caldera was created by a cataclysmic eruption that occurred 640 000 years ago which released more than 240 cubic miles 1 000 km of ash rock and pyroclastic materials 84 This eruption was more than 1 000 times larger than the 1980 eruption of Mount St Helens 85 It produced a caldera nearly 5 8 of a mile 1 km deep and 45 by 28 miles 72 by 45 km in area and deposited the Lava Creek Tuff a welded tuff geologic formation The most violent known eruption which occurred 2 1 million years ago ejected 588 cubic miles 2 450 km of volcanic material and created the rock formation known as the Huckleberry Ridge Tuff and created the Island Park Caldera 86 A smaller eruption ejected 67 cubic miles 280 km of material 1 3 million years ago forming the Henry s Fork Caldera and depositing the Mesa Falls Tuff 85 Each of the three climactic eruptions released vast amounts of ash that blanketed much of central North America falling many hundreds of miles away The amount of ash and gases released into the atmosphere probably caused significant impacts on world weather patterns and led to the extinction of some species primarily in North America 87 Boardwalks allow visitors to safely approach the thermal features such as Grand Prismatic Spring A subsequent caldera forming eruption occurred about 160 000 years ago It formed the relatively small caldera that contains the West Thumb of Yellowstone Lake Since the last supereruption a series of smaller eruptive cycles between 640 000 and 70 000 years ago has nearly filled in the Yellowstone Caldera with 80 different eruptions of rhyolitic lavas such as those that can be seen at Obsidian Cliffs and basaltic lavas which can be viewed at Sheepeater Cliff Lava strata are most easily seen at the Grand Canyon of the Yellowstone where the Yellowstone River continues to carve into the ancient lava flows The canyon is a classic V shaped valley indicative of river type erosion rather than erosion caused by glaciation 86 Each eruption is part of an eruptive cycle that climaxes with the partial collapse of the roof of the volcano s partially emptied magma chamber This creates a collapsed depression called a caldera and releases vast amounts of volcanic material usually through fissures that ring the caldera The time between the last three cataclysmic eruptions in the Yellowstone area has ranged from 600 000 to 800 000 years but the small number of such climactic eruptions cannot be used to make an accurate prediction for future volcanic events 88 Geysers and the hydrothermal system Edit See also List of Yellowstone geothermal features Old Faithful erupts approximately every 90 minutes Steamboat Geyser is the world s largest active geyser The most famous geyser in the park and perhaps the world is Old Faithful geyser located in Upper Geyser Basin Castle Geyser Lion Geyser Beehive Geyser Grand Geyser the world s tallest predictable geyser Giant Geyser the world s most voluminous geyser Riverside Geyser and numerous other geysers are in the same basin The park contains the tallest active geyser in the world Steamboat Geyser in the Norris Geyser Basin A study that was completed in 2011 found that at least 1283 geysers have erupted in Yellowstone Of these an average of 465 are active in a given year 89 90 Yellowstone contains at least 10 000 thermal features altogether including geysers hot springs mudpots and fumaroles 91 Over half of the world s geysers and hydrothermal features are concentrated in Yellowstone 92 17 In May 2001 the U S Geological Survey Yellowstone National Park and the University of Utah created the Yellowstone Volcano Observatory YVO a partnership for long term monitoring of the geological processes of the Yellowstone Plateau volcanic field for disseminating information concerning the potential hazards of this geologically active region 93 In 2003 changes at the Norris Geyser Basin resulted in the temporary closure of some trails in the basin New fumaroles were observed and several geysers showed enhanced activity and increasing water temperatures Several geysers became so hot that they were transformed into purely steaming features the water had become superheated and they could no longer erupt normally 94 This coincided with the release of reports of a multiple year United States Geological Survey research project which mapped the bottom of Yellowstone Lake and identified a structural dome that had uplifted at some time in the past Research indicated that these uplifts posed no immediate threat of a volcanic eruption since they may have developed long ago and there had been no temperature increase found near the uplifts 95 On March 10 2004 a biologist discovered 5 dead bison which apparently had inhaled toxic geothermal gases trapped in the Norris Geyser Basin by a seasonal atmospheric inversion This was closely followed by an upsurge in earthquake activity in April 2004 96 In 2006 it was reported that the Mallard Lake Dome and the Sour Creek Dome areas that have long been known to show significant changes in their ground movement had risen at a rate of 1 5 to 2 4 inches 3 8 to 6 1 cm per year from mid 2004 through 2006 As of late 2007 the uplift has continued at a reduced rate 97 98 These events inspired a great deal of media attention and speculation about the geologic future of the region Experts responded to the conjecture by informing the public that there was no increased risk of a volcanic eruption in the near future 99 However these changes demonstrate the dynamic nature of the Yellowstone hydrothermal system Earthquakes Edit Infrastructure damage at Hebgen Lake due to the 7 2 magnitude earthquake of 1959 Yellowstone experiences thousands of small earthquakes every year virtually all of which are undetectable to people There have been six earthquakes with at least magnitude 6 or greater in historical times including the 7 2 magnitude Hebgen Lake earthquake which occurred just outside the northwest boundary of the park in 1959 100 This quake triggered a huge landslide which caused a partial dam collapse on Hebgen Lake immediately downstream the sediment from the landslide dammed the river and created a new lake known as Earthquake Lake Twenty eight people were killed and property damage was extensive in the immediate region The earthquake caused some geysers in the northwestern section of the park to erupt large cracks in the ground formed and emitted steam and some hot springs that normally have clear water turned muddy 67 A 6 1 magnitude earthquake struck inside the park on June 30 1975 but the damage was minimal For three months in 1985 3 000 minor earthquakes were detected in the northwestern section of the park during what has been referred to as an earthquake swarm and has been attributed to minor subsidence of the Yellowstone caldera 85 Beginning on April 30 2007 16 small earthquakes with magnitudes up to 2 7 occurred in the Yellowstone Caldera for several days These swarms of earthquakes are common and there have been 70 such swarms between 1983 and 2008 101 In December 2008 over 250 earthquakes were measured over four days under Yellowstone Lake the largest measuring a magnitude of 3 9 102 In January 2010 more than 250 earthquakes were detected over two days 103 Seismic activity in Yellowstone National Park continues and is reported hourly by the Earthquake Hazards Program of the U S Geological Survey 104 On March 30 2014 a magnitude 4 8 earthquake struck almost the very middle of Yellowstone near the Norris Basin at 6 34 am reports indicated no damage This was the largest earthquake to hit the park since February 22 1980 105 Biology and ecology EditMain articles Greater Yellowstone Ecosystem and Ecology of the Rocky Mountains Meadow in Yellowstone National Park Yellowstone National Park is the centerpiece of the 20 million acres 80 940 km2 31 250 sq mi Greater Yellowstone Ecosystem a region that includes Grand Teton National Park adjacent National Forests and expansive wilderness areas in those forests The ecosystem is the largest remaining continuous stretch of mostly undeveloped pristine land in the contiguous United States considered the world s largest intact ecosystem in the northern temperate zone 18 With the successful wolf reintroduction program which began in the 1990s virtually all the original faunal species known to inhabit the region when white explorers first entered the area can be found there citation needed Flora Edit Over 1 700 species of trees and other vascular plants are native to the park Another 170 species are considered to be exotic species and are non native Of the eight conifer tree species documented Lodgepole Pine forests cover 80 of the total forested areas 11 Other conifers such as Subalpine Fir Engelmann Spruce Rocky Mountain Douglas fir and Whitebark Pine are found in scattered groves throughout the park As of 2007 needs update the whitebark pine is threatened by a fungus known as white pine blister rust however this is mostly confined to forests well to the north and west In Yellowstone about seven percent of the whitebark pine species have been impacted with the fungus compared to nearly complete infestations in northwestern Montana 106 Quaking Aspen and willows are the most common species of deciduous trees The aspen forests have declined significantly since the early 20th century but scientists at Oregon State University attribute the recent recovery of the aspen to the reintroduction of wolves which has changed the grazing habits of local elk 107 Yellowstone sand verbena are endemic to Yellowstone s lakeshores There are dozens of species of flowering plants that have been identified most of which bloom between May and September 108 The Yellowstone sand verbena is a rare flowering plant found only in Yellowstone It is closely related to species usually found in much warmer climates making the sand verbena an enigma The estimated 8 000 examples of this rare flowering plant all make their home in the sandy soils on the shores of Yellowstone Lake well above the waterline 109 Microbial mat in cooled geyser water Upper Geyser Basin Orange and brown tinted microbes growing in sulfur rich waters near Anemone Geyser In Yellowstone s hot waters bacteria form mats of bizarre shapes consisting of trillions of individuals These bacteria are some of the most primitive life forms on earth Flies and other arthropods live on the mats even in the middle of the bitterly cold winters Initially scientists thought that microbes there gained sustenance only from sulfur In 2005 researchers from the University of Colorado at Boulder discovered that the sustenance for at least some of the diverse hyperthermophilic species is molecular hydrogen 110 Thermus aquaticus is a bacterium found in the Yellowstone hot springs that produces an important enzyme Taq polymerase that is easily replicated in the lab and is useful in replicating DNA as part of the polymerase chain reaction PCR process The retrieval of these bacteria can be achieved with no impact on the ecosystem Other bacteria in the Yellowstone hot springs may also prove useful to scientists who are searching for cures for various diseases 111 In 2016 researchers from Uppsala University reported the discovery of a class of thermophiles Hadesarchaea in Yellowstone s Culex Basin These organisms are capable of converting carbon monoxide and water to carbon dioxide and hydrogen 112 113 Non native plants sometimes threaten native species by using up nutrient resources Though exotic species are most commonly found in areas with the greatest human visitation such as near roads and at major tourist areas they have also spread into the backcountry Generally most exotic species are controlled by pulling the plants out of the soil or by spraying both of which are time consuming and expensive 114 Fauna Edit Main articles Animals of Yellowstone Birds of Yellowstone National Park History of wolves in Yellowstone Yellowstone Park Bison Herd Small mammals of Yellowstone National Park Fishes of Yellowstone National Park and Amphibians and reptiles of Yellowstone National Park Yellowstone is widely considered to be the finest megafauna wildlife habitat in the lower 48 states There are almost 60 species of mammals in the park including the Rocky Mountain wolf coyote the Canadian lynx cougars and black and grizzly bears 11 Other large mammals include the bison often referred to as buffalo elk moose mule deer white tailed deer mountain goat pronghorn and bighorn sheep American bison The Yellowstone Park bison herd is the largest public herd of American bison in the United States Bison once numbered between 30 and 60 million individuals throughout North America and Yellowstone remains one of their last strongholds Their populations had increased from less than 50 in the park in 1902 to 4 000 by 2003 The Yellowstone Park bison herd reached a peak in 2005 with 4 900 animals Despite a summer estimated population of 4 700 in 2007 the number dropped to 3 000 in 2008 after a harsh winter and controversial brucellosis management strategies which sent hundreds to slaughter 115 Elk mother nursing her calf The Yellowstone Park bison herd is believed to be one of only four free roaming and genetically pure herds on public lands in North America The other three herds are the Henry Mountains bison herd of Utah at Wind Cave National Park in South Dakota and in Elk Island National Park in Alberta 116 The relatively large bison populations are a concern for ranchers who fear that the species can transmit bovine diseases to their domesticated cousins About half of Yellowstone s bison have been exposed to brucellosis a bacterial disease that came to North America with European cattle that may cause cattle to miscarry The disease has little effect on park bison and no reported cases of transmission from wild bison to domestic livestock have been filed However the Animal and Plant Health Inspection Service APHIS has stated that bison are the likely source of the spread of the disease in cattle in Wyoming and North Dakota Elk also carry the disease and are believed to have transmitted the infection to horses and cattle 117 To combat the perceived threat of brucellosis transmission to cattle national park personnel regularly corral bison herds back into the park when they venture outside of the area s borders During the winter of 1996 97 the bison herd was so large that 1 079 bison that had exited the park were either shot or sent to slaughter 117 Animal rights activists argue that this is a cruel practice and that the possibility for disease transmission is not as great as some ranchers maintain Ecologists point out that the bison are merely traveling to seasonal grazing areas that lie within the Greater Yellowstone Ecosystem that have been converted to cattle grazing some of which are within National Forests and are leased to private ranchers APHIS has stated that with vaccinations and other means brucellosis can be eliminated from the bison and elk herds throughout Yellowstone 117 A reintroduced wolf in Yellowstone National Park Starting in 1914 to protect elk populations the U S Congress appropriated funds to be used for destroying wolves prairie dogs and other animals injurious to agriculture and animal husbandry on public lands Park Service hunters carried out these orders and by 1926 they had killed 136 wolves Gradually wolves were virtually eliminated from Yellowstone 118 Further exterminations continued until the National Park Service ended the practice in 1935 With the passing of the Endangered Species Act in 1973 the wolf was one of the first mammal species listed 118 After the wolves were extirpated from Yellowstone the coyote then became the park s top canine predator Since the coyote is not able to bring down large animals this lack of an apex predator resulted in a marked increase in lame and sick megafauna citation needed By the 1990s the Federal government had reversed its views on wolves In a controversial decision by the U S Fish and Wildlife Service which oversees threatened and endangered species northwestern wolves imported from Canada were reintroduced into the park Reintroduction efforts have been successful with populations remaining relatively stable A survey conducted in 2005 reported that there were 13 wolf packs totaling 118 individuals in Yellowstone and 326 in the entire ecosystem These park figures were lower than those reported in 2004 but may be attributable to wolf migration to other nearby areas as suggested by the substantial increase in the Montana population during that interval 119 Almost all the wolves documented were descended from the 66 wolves reintroduced in 1995 96 119 The recovery of populations throughout the states of Wyoming Montana and Idaho has been so successful that on February 27 2008 the U S Fish and Wildlife Service removed the Northern Rocky Mountain wolf population from the endangered species list 120 Black bear and cub near Tower Fall Black bears are common in the park and were a park symbol due to visitor interaction with the bears starting in 1910 Feeding and close contact with bears has not been permitted since the 1960s to reduce their desire for human foods 121 Yellowstone is one of the few places in the United States where black bears can be seen coexisting with grizzly bears 121 Black bear observations occur most often in the park s northern ranges and in the Bechler area which is in the park s southwestern corner 122 As of 2017 update an estimated 700 grizzly bears were living in the Greater Yellowstone Ecosystem 123 with about 150 grizzlies living wholly or partially within Yellowstone National Park 124 The grizzly was initially listed as a threatened species in the contiguous United States on July 28 1975 by the Fish and Wildlife Service The grizzly bear was taken off the endangered species list in 2007 125 Opponents of delisting the grizzly expressed concerns that states might once again allow hunting and that better conservation measures were needed to ensure a sustainable population 126 A federal district judge overturned the delisting ruling in 2009 reinstating the grizzly however the grizzly was once again removed from the list in 2017 125 In September 2018 a US district judge ruled that the grizzly s protections must be restored in full arguing the Fish and Wildlife Service was mistaken in removing the bear from the threatened status list 127 Regardless of the rulings hunting is prohibited within Yellowstone National Park Hunters who legally hunt animals outside park boundaries may transport the carcass through the park with a permit 128 Elk in Hayden Valley Population figures for elk are more than 30 000 the largest population of any large mammal species in Yellowstone The northern herd has decreased enormously since the mid 1990s this has been attributed to wolf predation and causal effects such as elk using more forested regions to evade predation consequently making it harder for researchers to accurately count them 129 The northern herd migrates west into southwestern Montana in the winter The southern herd migrates southward and the majority of this elk winter on the National Elk Refuge immediately southeast of Grand Teton National Park The southern herd migration is the largest mammalian migration remaining in the U S outside of Alaska citation needed In 2003 the tracks of one female lynx and her cub were spotted and followed for over 2 miles 3 2 km Fecal material and other evidence obtained were tested and confirmed to be those of a lynx No visual confirmation was made however Lynx have not been seen in Yellowstone since 1998 though DNA taken from hair samples obtained in 2001 confirmed that lynx were at least transient to the park 130 Other less commonly seen mammals include the mountain lion and wolverine The mountain lion has an estimated population of only 25 individuals parkwide 131 Accurate population figures for the wolverine are not known 132 These uncommon and rare mammals provide insight into the health of protected lands such as Yellowstone and help managers make determinations as to how best to preserve habitats Pronghorn are commonly found on the grasslands in the park Eighteen species of fish live in Yellowstone including the core range of the Yellowstone cutthroat trout a fish highly sought by anglers 11 133 The Yellowstone cutthroat trout has faced several threats since the 1980s including the suspected illegal introduction into Yellowstone Lake of lake trout an invasive species which consume the smaller cutthroat trout 134 Although lake trout were established in Shoshone and Lewis lakes on the Snake River drainage after U S Government stocking operations in 1890 it was never officially introduced into the Yellowstone River drainage 135 The cutthroat trout has also faced an ongoing drought as well as the accidental introduction of a parasite whirling disease which causes a terminal nervous system disease in younger fish Since 2001 all native sport fish species caught in Yellowstone waterways are subject to catch and release regulations 133 Yellowstone is also home to seven species of reptiles including the painted turtle rubber Rubber boa and prairie rattlesnake bullsnake sagebrush lizard valley garter snake and wandering garter snake and four species of amphibians including the boreal chorus frog tiger salamander western toad and columbia spotted frog 136 Three hundred eleven species of birds have been reported almost half of which nest in Yellowstone 11 In 1999 twenty six pairs of nesting bald eagle were documented Extremely rare sightings of whooping cranes have been recorded however only three examples of this species are known to live in the Rocky Mountains out of 385 known worldwide 137 Other birds considered to be species of special concern because of their rarity in Yellowstone include the common loon harlequin duck osprey peregrine falcon and the trumpeter swan 138 Forest fires EditSee also Yellowstone fires of 1988 and 1988 89 North American drought Fire in Yellowstone National Park As wildfire is a natural part of most ecosystems plants that are indigenous to Yellowstone have adapted in a variety of ways Douglas fir have a thick bark that protects the inner section of the tree from most fires Lodgepole Pines the most common tree species in the park generally have cones that are only opened by the heat of a fire Their seeds are held in place by a tough resin and fire assists in melting the resin allowing the seeds to disperse Fire clears out dead and downed wood providing fewer obstacles for lodgepole pines to flourish Subalpine Fir Engelmann Spruce Whitebark Pine and other species tend to grow in colder and moister areas where the fire is less likely to occur Aspen trees sprout new growth from their roots and even if a severe fire kills the tree above ground the roots often survive unharmed because they are insulated from the heat by soil 139 The National Park Service estimates that in natural conditions grasslands in Yellowstone burned an average of every 20 to 25 years while forests in the park would experience fire about every 300 years 139 About thirty five natural forest fires are ignited each year by lightning while another six to ten are started by people in most cases by accident Yellowstone National Park has three fire lookout towers each staffed by trained firefighters The easiest one to reach is atop Mount Washburn which has interpretive exhibits and an observation deck open to the public 140 The park also monitors fire from the air and relies on visitor reports of smoke and or flames 141 Fire towers are staffed almost continuously from late June to mid September the primary fire season Fires burn with the greatest intensity in the late afternoon and evening Few fires burn more than 100 acres 40 ha and the vast majority of fires reach only a little over an acre 0 5 ha before they burn themselves out 142 Fire management focuses on monitoring dead and down wood quantities soil and tree moisture and the weather to determine those areas most vulnerable to fire should one ignite The current policy is to suppress all human caused fires and to evaluate natural fires examining the benefit or detriment they may pose to the ecosystem If a fire is considered to be an immediate threat to people and structures or will burn out of control then fire suppression is performed 143 Wildfire in Yellowstone National Park produces a pyrocumulus cloud To minimize the chances of out of control fires and threats to people and structures park employees do more than just monitor the potential for fire Controlled burns are prescribed fires that are deliberately started to remove dead timber under conditions that allow firefighters an opportunity to carefully control where and how much wood is consumed Natural fires are sometimes considered prescribed fires if they are left to burn In Yellowstone unlike some other parks there have been very few fires deliberately started by employees as prescribed burns However over the last 30 years over 300 natural fires have been allowed to burn naturally In addition firefighters remove dead and down wood and other hazards from areas where they will be a potential fire threat to lives and property reducing the chances of fire danger in these areas 144 Fire monitors also regulate fire through educational services to the public and have been known to temporarily ban campfires from campgrounds during periods of high fire danger The common notion in early United States land management policies was that all forest fires were bad The fire was seen as a purely destructive force and there was little understanding that it was an integral part of the ecosystem Consequently until the 1970s when a better understanding of wildfire was developed all fires were suppressed This led to an increase in dead and dying forests which would later provide the fuel load for fires that would be much harder and in some cases impossible to control The latest Fire Management Plan 2014 allows natural fires to burn if they posed no immediate threat to lives and property 145 A crown fire approaches the Old Faithful complex on September 7 1988 The spring season of 1988 was wet but by summer drought began moving in throughout the northern Rockies creating the driest year on record to that point Grasses and plants which grew well in the early summer from the abundant spring moisture produced plenty of grass which soon turned to dry tinder The National Park Service began firefighting efforts to keep the fires under control but the extreme drought made suppression difficult Between July 15 and 21 1988 fires quickly spread from 8 500 acres 3 400 ha 13 3 sq mi throughout the entire Yellowstone region which included areas outside the park to 99 000 acres 40 000 ha 155 sq mi on the park land alone By the end of the month the fires were out of control Large fires burned together and on August 20 1988 the single worst day of the fires more than 150 000 acres 61 000 ha 230 sq mi were consumed Seven large fires were responsible for 95 of the 793 000 acres 321 000 ha 1 239 sq mi that were burned over the next couple of months The cost of 25 000 firefighters and U S military forces participating in the suppression efforts was 120 million dollars By the time winter brought snow that helped extinguish the last flames the fires had destroyed 67 structures and caused several million dollars in damage 69 Though no civilians died two personnel associated with the firefighting efforts were killed 146 Contrary to media reports and speculation at the time the fires killed very few park animals surveys indicated that only about 345 elk of an estimated 40 000 50 000 36 deer 12 moose 6 black bears and 9 bison had perished Changes in fire management policies were implemented by land management agencies throughout the United States based on knowledge gained from the 1988 fires and the evaluation of scientists and experts from various fields By 1992 Yellowstone had adopted a new fire management plan which observed stricter guidelines for the management of natural fires 69 Climate and weather Edit Winter scene in Yellowstone Geyser at Yellowstone Lake Yellowstone s climate is greatly influenced by altitude with lower elevations generally found to be warmer year round The record high temperature was 99 F 37 C in 2002 while the coldest temperature recorded is 66 F 54 C in 1933 11 During the summer months of June to early September daytime highs are normally in the 70 to 80 F 21 to 27 C range while nighttime lows can go to below freezing 0 C especially at higher altitudes Summer afternoons are frequently accompanied by thunderstorms Spring and fall temperatures range between 30 and 60 F 1 and 16 C with nights in the teens to single digits 5 to 20 C Winter in Yellowstone is accompanied by high temperatures usually between zero and 20 F 20 to 5 C and nighttime temperatures below 0 F 18 C for most of the winter 147 Precipitation in Yellowstone is highly variable and ranges from 15 inches 380 mm annually near Mammoth Hot Springs to 80 inches 2 000 mm in the southwestern sections of the park The precipitation of Yellowstone is greatly influenced by the moisture channel formed by the Snake River Plain to the west that was in turn formed by Yellowstone itself Snow is possible in any month of the year but most common between November and April with averages of 150 inches 3 800 mm annually around Yellowstone Lake to twice that amount at higher elevations 147 The climate at Yellowstone Lake is classified as subarctic Dfc according to Koppen Geiger climate classification while at the park headquarters the classification is humid continental Dfb Tornadoes in Yellowstone are rare however on July 21 1987 the most powerful tornado recorded in Wyoming touched down in the Teton Wilderness of Bridger Teton National Forest and hit Yellowstone National Park Called the Teton Yellowstone tornado it was classified as an F4 with wind speeds estimated at between 207 and 260 miles per hour 333 and 418 km h The tornado left a path of destruction 1 to 2 miles 1 6 to 3 2 km wide and 24 miles 39 km long and leveled 15 000 acres 6 100 ha 23 sq mi of mature pine forest 148 In June 2022 the park closed entrances and evacuated visitors after experiencing record level rainfall and flooding that caused multiple road and bridge failures power outages and mudslides 149 A combination of heavy rain and rapid snow melt resulted in the Yellowstone River rising to a new record height at 13 88 feet 4 23 m breaking a previous record of 11 5 feet 3 5 m set in 1918 150 Flooding on the Lamar River reached 16 7 feet 5 1 m beating a 1996 record of 12 15 feet 3 70 m 151 Damage from the flooding includes washed out roads and bridges and damage to infrastructure systems including electricity water and wastewater systems It s unlikely that the park will be able to reopen the north entrance by Gardiner MT or the northeast entrance near Cooke City MT during the 2022 season 152 The park partially reopened Wednesday June 22 after a 9 day closure To limit the nearly one million visitors per month that visit in the summer the park has restricted entry to cars based on license plates Cars with license plates ending in even numbers can enter on even numbered dates and plates ending in odd numbers can enter on odd numbered dates 153 Climate data for Yellowstone Lake 1991 2020 normals extremes 1904 presentMonth Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec YearRecord high F C 48 9 49 9 60 16 73 23 78 26 84 29 92 33 91 33 89 32 76 24 63 17 52 11 92 33 Mean maximum F C 37 2 2 9 40 7 4 8 49 9 9 9 56 3 13 5 66 6 19 2 75 6 24 2 81 2 27 3 81 1 27 3 76 4 24 7 64 6 18 1 49 0 9 4 37 3 2 9 82 7 28 2 Average high F C 23 2 4 9 26 7 2 9 35 0 1 7 41 5 5 3 50 4 10 2 60 8 16 0 71 2 21 8 70 9 21 6 61 4 16 3 46 0 7 8 32 6 0 3 23 6 4 7 45 3 7 4 Daily mean F C 13 3 10 4 15 1 9 4 22 9 5 1 30 4 0 9 39 7 4 3 48 5 9 2 56 9 13 8 56 2 13 4 47 7 8 7 35 6 2 0 23 7 4 6 15 4 9 2 33 8 1 0 Average low F C 3 3 15 9 3 5 15 8 10 8 11 8 19 3 7 1 29 0 1 7 36 3 2 4 42 7 5 9 41 6 5 3 34 1 1 2 25 2 3 8 14 8 9 6 7 2 13 8 22 3 5 4 Mean minimum F C 21 2 29 6 23 2 30 7 13 4 25 2 0 6 18 1 12 2 11 0 25 0 3 9 31 7 0 2 29 4 1 4 21 5 5 8 6 8 14 0 7 1 21 7 14 6 25 9 28 1 33 4 Record low F C 51 46 56 49 43 42 29 34 10 23 14 10 20 7 13 11 5 21 17 27 30 34 48 44 56 49 Average precipitation inches mm 1 97 50 1 80 46 1 97 50 2 12 54 2 42 61 2 46 62 1 29 33 1 49 38 1 58 40 1 64 42 1 81 46 1 99 51 22 54 573 Average snowfall inches cm 35 8 91 30 9 78 25 1 64 22 9 58 6 9 18 1 0 2 5 0 0 0 0 0 0 0 0 1 4 3 6 10 2 26 29 8 76 35 4 90 199 4 507 1 Average precipitation days 0 01 in 17 2 15 1 13 9 12 3 11 3 13 4 9 9 10 4 9 7 9 2 12 3 16 5 151 2Average snowy days 0 1 in 16 3 14 4 12 3 10 2 4 3 0 8 0 0 0 0 0 8 5 5 11 8 15 4 91 8Source 1 NOAA 154 Source 2 National Weather Service 155 Climate data for Yellowstone National Park Mammoth Wyoming 1991 2020 normals extremes 1894 presentMonth Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec YearRecord high F C 53 12 56 13 66 19 78 26 86 30 92 33 99 37 97 36 92 33 81 27 66 19 57 14 99 37 Mean maximum F C 44 6 7 0 47 8 8 8 57 1 13 9 68 0 20 0 76 9 24 9 85 2 29 6 91 2 32 9 90 5 32 5 85 4 29 7 73 0 22 8 56 8 13 8 44 8 7 1 92 3 33 5 Average high F C 31 4 0 3 34 2 1 2 41 9 5 5 49 7 9 8 59 6 15 3 69 5 20 8 80 8 27 1 79 8 26 6 68 8 20 4 53 6 12 0 39 4 4 1 30 3 0 9 53 3 11 8 Daily mean F C 21 7 5 7 23 3 4 8 30 5 0 8 38 0 3 3 47 1 8 4 55 8 13 2 64 6 18 1 63 1 17 3 53 9 12 2 41 3 5 2 29 3 1 5 21 1 6 1 40 8 4 9 Average low F C 11 9 11 2 12 3 10 9 19 1 7 2 26 3 3 2 34 6 1 4 42 0 5 6 48 3 9 1 46 5 8 1 39 0 3 9 28 9 1 7 19 2 7 1 11 9 11 2 28 3 2 1 Mean minimum F C 9 5 23 1 8 7 22 6 0 8 17 3 12 1 11 1 22 6 5 2 32 2 0 1 40 0 4 4 36 9 2 7 27 7 2 4 12 6 10 8 0 2 17 9 9 1 22 8 18 0 27 8 Record low F C 36 38 35 37 24 31 6 21 6 14 20 7 21 6 24 4 0 18 8 22 27 33 35 37 36 38 Average precipitation inches mm 0 91 23 0 79 20 1 09 28 1 40 36 1 82 46 1 86 47 1 27 32 1 05 27 1 21 31 1 34 34 1 15 29 0 91 23 14 80 376 Average snowfall inches cm 11 5 29 11 5 29 10 9 28 7 8 20 1 7 4 3 0 3 0 76 0 0 0 0 0 0 0 0 0 6 1 5 4 7 12 9 9 25 12 6 32 71 5 182 Average precipitation days 0 01 in 10 6 11 4 10 5 11 3 12 8 12 5 9 2 8 5 8 7 9 7 9 6 11 9 126 7Average snowy days 0 1 in 8 7 9 4 7 0 5 5 1 2 0 1 0 0 0 0 0 3 2 8 7 5 10 2 52 7Source NOAA 156 157 Recreation EditMain articles Trails of Yellowstone National Park and Angling in Yellowstone National Park Union Pacific Railroad brochure promoting travel to the park 1921 Yellowstone ranks among the most popular national parks in the United States Since the mid 1960s at least 2 million tourists have visited the park almost every year 158 Average annual visitation increased to 3 5 million during the ten years from 2007 to 2016 with a record of 4 257 177 recreational visitors in 2016 159 July is the busiest month for Yellowstone National Park 160 At peak summer levels 3 700 employees work for Yellowstone National Park concessionaires Concessionaires manage nine hotels and lodges with a total of 2 238 hotel rooms and cabins available They also oversee gas stations stores and most of the campgrounds Another 800 employees work either permanently or seasonally for the National Park Service 11 Tourists watch Old Faithful erupt 2019 Park service roads lead to major features however road reconstruction has produced temporary road closures Yellowstone is in the midst of a long term road reconstruction effort which is hampered by a short repair season In the winter all roads aside from the one which enters from Gardiner Montana and extends to Cooke City Montana are closed to wheeled vehicles 161 Park roads are closed to wheeled vehicles from early November to mid April but some park roads remain closed until mid May 162 The park has 310 miles 500 km of paved roads which can be accessed from five different entrances 11 There is no public transportation available inside the park but several tour companies can be contacted for guided including self guided motorized transport In the winter concessionaires operate guided snowmobile and snow coach tours though their numbers and access are based on quotas established by the National Park Service 163 Facilities in the Old Faithful Canyon and Mammoth Hot Springs areas of the park are very busy during the summer months Traffic jams created by road construction or by people observing wildlife can result in long delays The National Park Service maintains nine visitor centers and museums and is responsible for the maintenance of historical structures and many of the other 2 000 buildings These structures include National Historical Landmarks such as the Old Faithful Inn built from 1903 to 1904 and the entire Fort Yellowstone Mammoth Hot Springs Historic District A historical and educational tour is available at Fort Yellowstone which details the history of the National Park Service and the development of the park Campfire programs guided walks and other interpretive presentations normally available at numerous locations in the summer and on a limited basis during other seasons were suspended in 2021 as a COVID 19 response 164 Camping is available at a dozen campgrounds with more than 2 000 campsites 11 Camping is also available in surrounding National Forests as well as in Grand Teton National Park to the south Backcountry campsites are accessible only by foot or by horseback and require a permit There are 1 100 miles 1 800 km of hiking trails available 165 The park is not considered to be a good destination for mountaineering because of the instability of volcanic rock which predominates Visitors with pets are required to keep them on a leash at all times and are limited to areas near roadways and in front country zones such as drive in campgrounds 166 Around thermal features wooden and paved trails have been constructed to ensure visitor safety and most of these areas are handicapped accessible The National Park Service maintains a year round clinic at Mammoth Hot Springs and provides emergency services throughout the year 167 Hunting is not permitted though it is allowed in the surrounding national forests during the open season Fishing is a popular activity and a Yellowstone Park fishing license is required to fish in park waters 168 Many park waters are fly fishing only and all native fish species are catch and release only 169 Boating is prohibited on rivers and creeks except for a 5 miles 8 0 km stretch of the Lewis River between Lewis and Shoshone lakes and it is open to non motorized use only Yellowstone Lake has a marina at Bridge Bay while there is a boat ramp at the Lewis lake campground 170 Vintage photo of human habituated bears seeking food from visitors In the early history of the park visitors were allowed and sometimes even encouraged to feed the bears Visitors welcomed the chance to get their pictures taken with the bears who had learned to beg for food This led to numerous injuries to humans each year In 1970 park officials changed their policy and started a vigorous program to educate the public on the dangers of close contact with bears and to try to eliminate opportunities for bears to find food in campgrounds and trash collection areas Although it has become more difficult to observe bears in recent years the number of human injuries and deaths has taken a significant drop and visitors are in less danger 171 The eighth recorded bear related death in the park s history occurred in August 2015 172 Other protected lands in the region include Caribou Targhee Gallatin Custer Shoshone and Bridger Teton National Forests The National Park Service s John D Rockefeller Jr Memorial Parkway is to the south and leads to Grand Teton National Park The famed Beartooth Highway provides access from the northeast and has spectacular high altitude scenery Nearby communities include West Yellowstone Montana Cody Wyoming Red Lodge Montana Ashton Idaho and Gardiner Montana The closest air transport is available by way of Bozeman Montana Billings Montana Jackson Cody Wyoming or Idaho Falls Idaho 173 Salt Lake City 320 miles 510 km to the south is the closest large metropolitan area Legal jurisdiction EditMain article Zone of Death Yellowstone Idaho portion of park highlighted in southwest corner click to enlarge The entire park is within the jurisdiction of the United States District Court for the District of Wyoming making it the only federal court district that includes portions of more than one state Idaho Montana and Wyoming Law professor Brian C Kalt has argued that it may be impossible to impanel a jury in compliance with the Vicinage Clause of the Sixth Amendment for a crime committed solely in the unpopulated Idaho portion of the park and that it would be difficult to do so for a crime committed solely in the lightly populated Montana portion 174 One defendant who was accused of a wildlife related crime in the Montana portion of the park attempted to raise this argument but eventually pleaded guilty with the plea deal including his specific agreement not to raise the issue in his appeal 175 176 177 See also EditBibliography of Yellowstone National Park List of national parks of the United States Making North America 2015 PBS film National Parks in Idaho Outline of Yellowstone National ParkReferences Edit Yellowstone in United States of America protectedplanet net IUCN Archived from the original on August 27 2019 Retrieved December 31 2018 Yellowstone National Park Geographic Names Information System United States Geological Survey United States Department of the Interior August 31 1992 Retrieved October 13 2020 a b c Listing of acreage December 31 2011 XLSX Land Resource Division National Park Service Retrieved March 8 2012 National Park Service Acreage Reports Annual Visitation Highlights nps gov National Park Service Archived from the original on February 9 2021 Retrieved July 8 2020 Yellowstone National Park UNESCO World Heritage Centre Archived from the original on February 24 2017 Retrieved March 24 2012 Yellowstone the First National Park Library of Congress Archived from the original on May 11 2017 An Act to set apart a certain tract of Land lying near the Head waters of the Yellowstone River as a Public Park PDF Library of Congress a b U S Statutes at Large Vol 17 Chap 24 pp 32 33 An Act to set apart a certain Tract of Land lying near the Headwaters of the Yellowstone River as a public Park S 392 Archived from the original on June 24 2013 Act Establishing Yellowstone National Park 1872 National Archives September 8 2021 Retrieved May 23 2022 Biosphere Reserve Information United States Yellowstone UNESCO MAB Biosphere Reserves Directory UNESCO August 17 2000 Archived from the original on August 4 2007 Retrieved August 14 2016 a b c d e f g h i j k l m n o p Park Facts National Park Service December 22 2015 Archived from the original on December 13 2015 Retrieved December 27 2015 Yellowstone History and Culture National Park Service Archived from the original on September 22 2013 Retrieved May 8 2011 eRecords of the National Park Service NPS National Archives Archived from the original on October 16 2014 Retrieved January 9 2016 Questions About Yellowstone Volcanic History United States Geological Survey Yellowstone Volcano Observatory Archived from the original on June 30 2011 Retrieved May 6 2011 Bryan T Scott 2008 The Geysers of Yellowstone Fourth ed University Press of Colorado p 9 Johnson JB Anderson JF Anthony RE Sciotto M April 15 2013 Detecting geyser activity with infrasound Journal of Volcanology and Geothermal Research 256 105 117 Bibcode 2013JVGR 256 105J doi 10 1016 j jvolgeores 2013 02 016 Archived from the original on August 5 2018 Retrieved August 5 2018 a b Yellowstone National Park Encyclopaedia Britannica Archived from the original on August 5 2018 Retrieved August 5 2018 Yellowstone s principal attractions however are its some 10 000 hydrothermal features which constitute roughly half of all those known in the world a b Schullery Paul The Greater Yellowstone Ecosystem Our Living Resources U S Geological Survey Archived from the original on September 25 2006 Retrieved March 13 2007 Rediscovering Yellowstone Enduring World Archived October 30 2016 at the Wayback Machine Retrieved July 16 2020 Macdonald James S Jr December 27 2006 History of Yellowstone as a Place Name Archived from the original on January 21 2013 Retrieved December 14 2008 Yellowstone A Brief History of the Park PDF U S Department of the Interior Archived from the original PDF on April 14 2008 Lahren Larry 2006 Homeland An archaeologist s view of Yellowstone Country s past Cayuse Press p 161 ISBN 978 0 9789251 0 9 Janeski Joel C 1987 Indians in Yellowstone National Park Salt Lake City Utah University of Utah Press ISBN 978 0 87480 724 0 Janetski Joel C 1987 Indians in Yellowstone National Park Salt Lake City Utah University of Utah Press ISBN 978 0 87480 724 0 Haines Aubrey L 2000 The Lewis and Clark Era 1805 1814 Yellowstone National Park Its Exploration and Establishment U S Department of the Interior Archived from the original on October 15 2006 Retrieved November 14 2006 Haines Aubrey L 2000 The Fur Trade Era 1818 42 Yellowstone National Park Its Exploration and Establishment U S Department of the Interior Archived from the original on October 15 2006 Retrieved November 15 2006 Baldwin Kenneth H 1976 Enchanted Enclosure Historic Roads in the National Park System Chapter 2 The Raynolds Expedition of 1860 Historical Division Office of the Chief Of Engineers United States Army Archived from the original on December 9 2011 Retrieved May 7 2011 Haines Aubrey L 1975 The Exploring Era 1851 63 Yellowstone National Park Its Exploration and Establishment U S Department of the Interior Archived from the original on October 15 2006 Retrieved November 14 2006 Haines Aubrey L 2000 The Folsom Party 1869 Yellowstone National Park Its Exploration and Establishment U S Department of the Interior Archived from the original on June 11 2007 Retrieved October 9 2007 Langford Nathaniel P 1905 The 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6 Archived from the original on January 3 2014 Retrieved June 11 2012 Marlene Deahl Merrill 2003 Yellowstone and the Great West Journals Letters and Images from the 1871 Hayden Expedition U of Nebraska Press pp 210 211 ISBN 978 0 8032 8289 6 Archived from the original on January 3 2014 Retrieved June 11 2012 a b Chittenden Hiram Martin 1915 The Yellowstone National Park Historical and Descriptive Cincinnati Stewart and Kidd Co pp 77 78 Jones William A 1875 Report Upon the Reconnaissance of Northwestern Wyoming Including Yellowstone National Park Made in the Summer of 1873 U S Government Printing Office p 1 ISBN 0331948184 Wheeler Olin Dunbar 2010 Enlarge Image Nathaniel Pitt Langford The Vigilante the Explorer the Expounder and First Superintendent of the Yellowstone Park Nabu Press ISBN 978 1 177 37550 4 Dilsaver Lary M William Wyckoff May 2005 The Political Geography of National Parks The Pacific Historical Review 74 2 237 266 doi 10 1525 phr 2005 74 2 237 Wuerthner 11 15 07 George 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National Park Wyoming Lundquist Laura August 2 2013 Dormant Yellowstone geyser erupts The Bozeman Daily Chronicle Vaughan R Greg Heasler Henry Jaworowski Cheryl Lowenstern Jacob B Keszthely Laszlo P 2014 Provisional Maps of Thermal Areas in Yellowstone National Park based on Satellite Thermal Infrared Imaging and Field Observations PDF U S Department of the Interior U S Geological Survey p 6 Scientific Investigations Report 2014 5137 Archived PDF from the original on March 1 2021 Retrieved August 9 2018 Yellowstone National Park World Heritage Sites UNESCO World Heritage Centre April 23 2007 Archived from the original on February 24 2017 Retrieved April 23 2007 Information about the Yellowstone Volcano Observatory Yellowstone Volcano Observatory U S Geological Survey February 2 2007 Archived from the original on May 14 2008 Retrieved March 12 2007 Notable Changes in Thermal Activity at Norris Geyser Basin Provide Opportunity to Study Hydrothermal System Yellowstone Volcano Observatory U S Geological Survey March 16 2005 Archived from the original on January 18 2012 Retrieved March 12 2007 Frequently asked questions about recent findings at Yellowstone Lake Yellowstone Volcano Observatory U S Geological Survey Archived from the original on February 4 2012 Retrieved March 12 2007 Archive of Stories About the Yellowstone Volcanic System Yellowstone Volcano Observatory U S Geological Survey February 2 2007 Archived from the original on February 10 2007 Retrieved March 12 2007 Earthquake Swarms at Yellowstone Continue Inland Park News December 19 2008 Archived from the original on May 20 2013 Retrieved August 24 2011 Smith Robert B Wu Lung Chang Lee Siegel November 8 2007 Yellowstone rising Volcano inflating with molten rock at record rate Press release University of Utah Public Relations EurekAlert American Association for the Advancement of Science Archived from the original on November 15 2007 Retrieved November 9 2007 Lowenstern Jake June 2005 Truth fiction and everything in between at Yellowstone Geotimes Archived from the original on February 3 2019 Retrieved March 12 2007 M 7 2 Hebgen Lake Wyoming Earthquake Archived November 28 2018 at the Wayback Machine earthquake usgs gov United States Geological Survey via the International Seismological Centre Retrieved November 28 2018 More Than A Dozen Earthquakes Shake Yellowstone KUTV News May 6 2007 Archived from the original on May 26 2007 Retrieved May 7 2007 Archive of Yellowstone Updates for 2008 Yellowstone Volcanic Observatory Archived from the original on January 23 2009 Retrieved December 31 2008 Yellowstone hit by swarm of earthquakes The Denver Post January 18 2010 Archived from the original on January 21 2010 Latest Earthquakes US Yellowstone Region United States Geological Survey Archived from the original on December 6 2008 4 8 Magnitude Earthquake Hits Yellowstone National Park Liberty Voice March 30 2014 Archived from the original on March 31 2014 Retrieved March 31 2014 Kendall Katherine Whitebark Pine Our Living Resources U S Geological Survey Archived from the original on September 27 2006 Retrieved March 13 2007 Presence Of Wolves Allows Aspen Recovery in Yellowstone Archived from the original on October 1 2007 Retrieved August 1 2007 Where Are the Bloomin Wildflowers PDF National Park Service February 2004 Archived PDF from the original on June 16 2007 Retrieved March 13 2007 Yellowstone Sand Verbena Nature and Science National Park Service July 20 2006 Archived from the original on June 7 2007 Retrieved March 13 2007 Microbes in Colorful Yellowstone Hot Springs Fueled By Hydrogen CU Boulder Researchers Say University of Colorado at Boulder January 24 2005 Archived from the original on April 26 2013 Retrieved March 13 2007 The Yellowstone Thermophiles Conservation Project World Foundation for Environment and Development April 27 2004 Archived from the original on March 20 2007 Retrieved March 15 2007 Baker Brett J Saw Jimmy H Lind Anders E Lazar Cassandra 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and Plant Health Inspection Service Archived from the original on February 28 2007 Retrieved August 24 2011 a b Defenders of Wildlife A Yellowstone Chronology Archived from the original on June 7 2007 Retrieved March 19 2007 a b Rocky Mountain Wolf Recovery 2005 Interagency Annual Report PDF U S Fish and Wildlife Service Nez Perce Tribe National Park Service Montana Fish Wildlife amp Parks Idaho Fish and Game and USDA Wildlife Services 2006 Archived PDF from the original on June 16 2007 Retrieved March 19 2007 Final Rule Designating the Northern Rocky Mountain Population of Gray Wolf as a Distinct Population Segment and Removing This Distinct Population Segment From the Federal List of Endangered and Threatened Wildlife U S Fish and Wildlife Service February 27 2008 Archived from the original on January 21 2009 Retrieved June 11 2008 a b Black Bears National Park Service March 31 2014 Archived from the original on April 18 2014 Retrieved April 16 2014 Black Bear Information Continued National Park Service April 3 2014 Archived from the original on April 18 2014 Retrieved April 16 2014 Frank T van Manen Mark A Haroldson and Bryn E Karabensh 2018 Yellowstone Grizzly Bear Investigations 2017 Annual Report of the Interagency Grizzly Bear Study Team archive page 23 of PDF file U S Geological Survey Wyoming Game and Fish Department National Park Service U S Fish and Wildlife Service Montana Fish Wildlife and Parks U S Forest Service Idaho Department of Fish and Game Eastern Shoshone and Northern Arapaho Tribal Fish and Game Department Retrieved December 19 2018 Grizzly Bears nps gov National Park Service April 2 2018 Archived from the original on October 10 2018 Retrieved December 19 2018 a b Grizzly Bears amp the Endangered Species Act nps gov National Park Service October 5 2018 Archived from the original on October 13 2018 Retrieved December 19 2018 Mott Maryann July 2 2004 Bald Eagle Grizzly U S Icons Endangered No More National Geographic News Archived from the original on December 10 2006 Retrieved March 19 2007 Jim Robbins September 25 2018 Hunt of Yellowstone Grizzly Bears Canceled as a Result of Judge s Ruling The New York Times Archived from the original on September 26 2018 Retrieved September 27 2018 Transporting Carcasses Through Yellowstone National Park Service Archived from the original on September 27 2018 Retrieved September 27 2018 2006 2007 Winter Count of Northern Yellowstone Elk National Park Service January 16 2007 Archived from the original on May 20 2007 Retrieved March 19 2007 Potter Tiffany April 13 2004 Reproduction of Canada Lynx Discovered in Yellowstone Nature Year in Review National Park Service Archived from the original on March 25 2007 Retrieved March 19 2007 Mountain Lions National Park Service July 26 2006 Archived from the original on September 3 2007 Retrieved March 19 2007 Marquis Amy Leinbach Summer 2006 Out of Sight Out of Mind National Parks 80 3 20 21 a b Fishing in Yellowstone National Park National Park Service April 4 2007 Archived from the original on November 9 2013 Retrieved March 19 2007 The Yellowstone Lake Crisis Confronting a Lake Trout Invasion PDF National Park Service 1995 Archived PDF from the original on June 12 2007 Retrieved March 19 2007 Kendall W C 1915 The Fishes of the Yellowstone National Park Washington D C Department of Commerce Bureau of Fisheries pp 22 23 Vital Habitats Wetlands and Wildlife PDF National Park Service Archived PDF from the original on June 16 2007 Retrieved March 19 2007 Threatened and Endangered Species National Park Service July 26 2006 Archived from the original on October 13 2007 Retrieved March 19 2007 Species of Special Concern National Park Service July 28 2006 Archived from the original on October 13 2007 Retrieved March 19 2007 a b Fire Ecology Yellowstone Wildland Fire National Park Service October 25 2006 Archived from the original on February 9 2007 Retrieved March 21 2007 Yellowstone National Park Mount Washburn Backpacker Magazine Cruz Bay Publishing Inc September 20 2013 Archived from the original on April 15 2017 Retrieved April 14 2017 Yellowstone Lookouts Yellowstone Wildland Fire National Park Service October 25 2006 Archived from the original on December 16 2006 Retrieved March 21 2007 Fire Facts Yellowstone Wildland Fire National Park Service October 25 2006 Archived from the original on April 25 2007 Retrieved March 21 2007 Fire Monitoring Yellowstone Wildland Fire National Park Service October 25 2006 Archived from the original on February 6 2007 Retrieved March 21 2007 Prescribed Fire Yellowstone Wildland Fire National Park Service October 25 2006 Archived from the original on June 10 2007 Retrieved March 21 2007 Yellowstone National Park 2014 Fire Management Plan PDF National Park Service April 17 2014 p 26 The Greater Yellowstone Fires of 1988 Questions and Answers PDF Greater Yellowstone Coordinating Committee February 2022 a b Weather National Park Service December 20 2006 Archived from the original on March 15 2007 Retrieved March 20 2007 Severe Weather Wyoming Climate Office March 14 2007 Archived from the original on February 19 2007 Retrieved March 20 2007 Christine Fernando and Hannah Phillips June 14 2022 Yellowstone National Park damaged by record flooding dangerous rockslides What we know USA Today Yellowstone closed after historic floods some areas cut off AP NEWS June 14 2022 Retrieved June 14 2022 writers Nicole Pollack and Joshua Wolfson Star Tribune staff All Yellowstone entrances closed due to flooding extremely hazardous conditions KPVI Archived from the original on June 13 2022 Retrieved June 14 2022 Yellowstone flood could close parts of the park all summer The Washington Post ISSN 0190 8286 Retrieved June 17 2022 Weitz Olivia June 22 2022 Yellowstone National Park partially reopens after floods NPR Retrieved June 24 2022 U S Climate Normals Quick Access National Oceanic and Atmospheric Administration Retrieved on August 19 2022 NOAA Online Weather Data National Weather Service Retrieved on August 19 2022 NOWData NOAA Online Weather Data National Oceanic and Atmospheric Administration Retrieved June 8 2021 Summary of Monthly Normals 1991 2020 National Oceanic and Atmospheric Administration Retrieved June 8 2021 Historical Annual Visitation Statistics Yellowstone National Park U S Department of the Interior August 10 2006 Archived from the original on October 14 2006 Retrieved December 13 2006 NPS Annual Recreation Visits Report National Park Service Retrieved March 11 2019 Cool Yellowstone becoming hotter vacation spot CNN Travel August 4 2010 Archived from the original on August 6 2010 Road Construction Delays and Closures National Park Service April 9 2007 Archived from the original on November 9 2013 Retrieved April 23 2007 Operating Hours amp Seasons National Park Service April 22 2007 Archived from the original on September 15 2013 Retrieved March 21 2007 Winter Services in Yellowstone National Park Service Archived from the original on November 9 2013 Retrieved March 21 2007 Ranger Programs nps gov March 2022 Hiking in the Park National Park Service August 17 2006 Archived from the original on April 3 2007 Retrieved March 21 2007 Regulations Regarding Pets National Park Service July 12 2006 Archived from the original on September 23 2013 Retrieved March 21 2007 Information Every Visitor Needs to Know National Park Service March 6 2007 Archived from the original on September 23 2013 Retrieved March 21 2007 Fishing in Yellowstone National Park National Park Service April 4 2007 Archived from the original on November 9 2013 Retrieved March 21 2007 2021 Yellowstone National Park Fishing Regulations PDF nps gov February 2021 Boating in Yellowstone National Park National Park Service September 18 2006 Archived from the original on November 9 2013 Retrieved March 21 2007 National Park Service Archived February 5 2011 at the Wayback Machine Bear Inflicted Human Injuries and Fatalities in Yellowstone U S National Park Service January 5 2015 Archived from the original on December 24 2015 Retrieved December 23 2015 Directions National Park Service January 4 2007 Archived from the original on September 23 2013 Retrieved January 4 2007 Brian C Kalt The Perfect Crime 93 Geo L J 675 2005 Morton Tom August 26 2007 The perfect place for the perfect crime Casper Star Tribune Archived from the original on February 17 2012 Retrieved July 18 2011 United States v Belderrain 309 F App x 259 10th Cir 2009 Brian C Kalt Tabloid Constitutionalism 96 Geo L J 1971 2008 Further reading EditWhittlesey Lee H 2002 Native Americans the Earliest Interpreters What is Known About Their Legends and Stories of Yellowstone National Park and the Complexities of Interpreting Them The George Wright Forum published by the George Wright Society Vol 19 No 3 pp 40 51 JSTOR 43598916 External links EditYellowstone National Park at Wikipedia s sister projects Media from Commons Texts from Wikisource Travel information from Wikivoyage Official website of the National Park Service Travertine Yellowstone s Hydrothermal Timekeeper USGS May 24 2021 Act Establishing Yellowstone National Park from the Library of Congress Congressional Acts Pertaining to Yellowstone The Yellowstone magmatic system from the mantle plume to the upper crust at Science registration required BYU Larsen Yellowstone collection at the L Tom Perry Special Collections Library of Brigham Young University Yellowstone articles photos and videos at National Geographic Photographic library of the U S Geological Survey archive The short film A Visit to Yellowstone National Park c 1932 is available for free download at the Internet Archive The short film Four Seasons of Yellowstone 1970 is available for free download at the Internet Archive The short film Fantastic Yellowstone 1997 is available for free download at the Internet Archive Historic American Engineering Record HAER documentation HAER No MT 91 West Entrance Road West Yellowstone Gallatin County MT 11 data pages HAER No MT 92 Gallatin Entrance Road West Yellowstone Gallatin County MT 15 data pages HAER No MT 93 North Entrance Road Gardiner Park County MT 1 color transparency 10 data pages 1 photo caption page Retrieved from https en wikipedia org w index php title Yellowstone National Park amp oldid 1141212274, wikipedia, wiki, book, books, library,

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