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Downburst

In meteorology, a downburst is a strong downward and outward gushing wind system that emanates from a point source above and blows radially, that is, in straight lines in all directions from the area of impact at surface level. Capable of producing damaging winds, it may sometimes be confused with a tornado, where high-velocity winds circle a central area, and air moves inward and upward. These usually last for seconds to minutes. Downbursts are particularly strong downdrafts within thunderstorms (or deep, moist convection as sometimes downbursts emanate from cumulonimbus or even cumulus congestus clouds that are not producing lightning).

Illustration of a microburst. The air moves in a downward motion until it hits the surface. It then spreads outward in all directions. The wind regime in a microburst is opposite to that of a tornado.

Downbursts are most often created by an area of significantly precipitation-cooled air that, after reaching the surface (subsiding), spreads out in all directions producing strong winds. Dry downbursts are associated with thunderstorms that exhibit very little rain, while wet downbursts are created by thunderstorms with significant amounts of precipitation.[1] Microbursts and macrobursts are downbursts at very small and larger scales, respectively. A rare variety of dry downburst, the heat burst, is created by vertical currents on the backside of old outflow boundaries and squall lines where rainfall is lacking. Heat bursts generate significantly higher temperatures due to the lack of rain-cooled air in their formation and compressional heating during descent. Downbursts create vertical wind shear, which is dangerous to aviation, especially during landing (or takeoff). Several fatal and historic crashes in past decades are attributed to the phenomenon and flight crew training goes to great lengths on how to properly recognize and recover from a downburst/wind shear event; wind shear recovery, among other adverse weather events, are standard topics across the world in flight simulator training that flight crews receive and must successfully complete. Detection and nowcasting technology was also implemented in much of the world and particularly around major airports, which in many cases actually have wind shear detection equipment on the field. This detection equipment helps air traffic controllers and pilots make decisions on the safety and feasibility of operating on or in the vicinity of the airport during storms. [2]

Definition edit

 
Downburst damages in a straight line

A downburst is created by a column of sinking air that after hitting the surface spreads out in all directions and is capable of producing damaging straight-line winds of over 240 km/h (150 mph), often producing damage similar to, but distinguishable from, that caused by tornadoes.[1] Downburst damage radiates from a central point as the descending column spreads out when hitting the surface, whereas tornado damage tends towards convergent damage consistent with rotating winds. To differentiate between tornado damage and damage from a downburst, the term straight-line winds is applied to damage from microbursts.

Downbursts in air that is precipitation free or contains virga are known as dry downbursts;[3] those accompanied with precipitation are known as wet downbursts. These generally are formed by precipitation-cooled air rushing to the surface, but they perhaps also could be powered by strong winds aloft being deflected toward the surface by dynamical processes in a thunderstorm (see rear flank downdraft).[citation needed] Most downbursts are less than 4 km (2.5 mi) in extent: these are called microbursts.[4] Downbursts larger than 4 km (2.5 mi) in extent are sometimes called macrobursts.[4] Downbursts can occur over large areas. In the extreme case, a series of continuing downbursts results in a derecho, which covers huge areas of more than 320 km (200 mi) wide and over 1,600 km (1,000 mi) long, persisting for 12 hours or more, and which is associated with some of the most intense straight-line winds,[5].

The term microburst was defined by mesoscale meteorology expert Ted Fujita as affecting an area 4 km (2.5 mi) in diameter or less, distinguishing them as a type of downburst and apart from common wind shear which can encompass greater areas.[6] Fujita also coined the term macroburst for downbursts larger than 4 km (2.5 mi).[7]

Dry microbursts edit

 
Dry microburst schematic

When rain falls below the cloud base or is mixed with dry air, it begins to evaporate and this evaporation process cools the air. The denser cool air descends and accelerates as it approaches the surface. When the cool air approaches the surface, it spreads out in all directions. High winds spread out in this type of pattern showing little or no curvature are known as straight-line winds.[8]

Dry microbursts are typically produced by high based thunderstorms that contain little to no surface rainfall. They occur in environments characterized by a thermodynamic profile exhibiting an inverted-V at thermal and moisture profile, as viewed on a Skew-T log-P thermodynamic diagram. Wakimoto (1985) developed a conceptual model (over the High Plains of the United States) of a dry microburst environment that comprised three important variables: mid-level moisture, cloud base in the mid troposphere, and low surface relative humidity. These conditions evaporate the moisture from the air as it falls, cooling the air and making it fall faster because it is more dense.

Wet microbursts edit

 
A wet microburst

Wet microbursts are downbursts accompanied by significant precipitation at the surface.[9] These downbursts rely more on the drag of precipitation for downward acceleration of parcels as well as the negative buoyancy which tend to drive "dry" microbursts. As a result, higher mixing ratios are necessary for these downbursts to form (hence the name "wet" microbursts). Melting of ice, particularly hail, appears to play an important role in downburst formation (Wakimoto and Bringi, 1988), especially in the lowest 1 km (0.6 mi) above surface level (Proctor, 1989). These factors, among others, make forecasting wet microbursts difficult.

Characteristic Dry Microburst Wet Microburst
Location of highest probability within the United States Midwest / West Southeast
Precipitation Little or none Moderate or heavy
Cloud bases As high as 500 hPa (mb) As high as 850 hPa (mb)
Features below cloud base Virga Precipitation shaft
Primary catalyst Evaporative cooling Precipitation loading and evaporative cooling
Environment below cloud base Deep dry layer/low relative humidity/dry adiabatic lapse rate Shallow dry layer/high relative humidity/moist adiabatic lapse rate

Straight-line winds edit

Straight-line winds (also known as plough winds, thundergusts and hurricanes of the prairie) are very strong winds that can produce damage, demonstrating a lack of the rotational damage pattern associated with tornadoes.[10] Straight-line winds are common with the gust front of a thunderstorm or originate with a downburst from a thunderstorm. These events can cause considerable damage, even in the absence of a tornado. The winds can gust to 58 m/s (130 mph)[11] and winds of 26 m/s (58 mph) or more can last for more than twenty minutes.[12] In the United States, such straight-line wind events are most common during the spring when instability is highest and weather fronts routinely cross the country.[citation needed] Straight-line wind events in the form of derechos can take place throughout the eastern half of the U.S.[13]

Straight-line winds may be damaging to marine interests. Small ships, cutters and sailboats are at risk from this meteorological phenomenon.[citation needed]

Formation edit

The formation of a downburst starts with hail or large raindrops falling through drier air. Hailstones melt and raindrops evaporate, pulling latent heat from surrounding air and cooling it considerably. Cooler air has a higher density than the warmer air around it, so it sinks to the surface. As the cold air hits the ground or water it spreads out and a mesoscale front can be observed as a gust front. Areas under and immediately adjacent to the downburst are the areas which receive the highest winds and rainfall, if any is present. Also, because the rain-cooled air is descending from the middle troposphere, a significant drop in temperatures is noticed. Due to interaction with the surface, the downburst quickly loses strength as it fans out and forms the distinctive "curl shape" that is commonly seen at the periphery of the microburst (see image). Downbursts usually last only a few minutes and then dissipate, except in the case of squall lines and derecho events. However, despite their short lifespan, microbursts are a serious hazard to aviation and property and can result in substantial damage to the area.

Downbursts go through three stages in their cycle: the downburst, outburst, and cushion stages.[14]

Development stages of microbursts edit

The evolution of microbursts is broken down into three stages: the contact stage, the outburst stage, and the cushion stage:[15]

  • A downburst initially develops as the downdraft begins its descent from the cloud base. The downdraft accelerates, and within minutes reaches the surface (contact stage).
  • During the outburst stage, the wind "curls" as the cold air of the downburst moves away from the point of impact with the surface.
  • During the cushion stage, winds about the curl continue to accelerate, while the winds at the surface slow due to friction.

On a weather radar Doppler display, a downburst is seen as a couplet of radial winds in the outburst and cushion stages. The rightmost image shows such a display from the ARMOR Doppler Weather Radar in Huntsville, Alabama in 2012. The radar is on the right side of the image and the downburst is along the line separating the velocity towards the radar (green), and the one moving away (red).

Physical processes of dry and wet microbursts edit

 

Basic physical processes using simplified buoyancy equations edit

Start by using the vertical momentum equation:

 

By decomposing the variables into a basic state and a perturbation, defining the basic states, and using the ideal gas law ( ), then the equation can be written in the form

 

where B is buoyancy. The virtual temperature correction usually is rather small and to a good approximation; it can be ignored when computing buoyancy. Finally, the effects of precipitation loading on the vertical motion are parametrized by including a term that decreases buoyancy as the liquid water mixing ratio ( ) increases, leading to the final form of the parcel's momentum equation:

 

The first term is the effect of perturbation pressure gradients on vertical motion. In some storms this term has a large effect on updrafts (Rotunno and Klemp, 1982) but there is not much reason to believe it has much of an impact on downdrafts (at least to a first approximation) and therefore will be ignored.

The second term is the effect of buoyancy on vertical motion. Clearly, in the case of microbursts, one expects to find that B is negative meaning the parcel is cooler than its environment. This cooling typically takes place as a result of phase changes (evaporation, melting, and sublimation). Precipitation particles that are small, but are in great quantity, promote a maximum contribution to cooling and, hence, to creation of negative buoyancy. The major contribution to this process is from evaporation.

The last term is the effect of water loading. Whereas evaporation is promoted by large numbers of small droplets, it only requires a few large drops to contribute substantially to the downward acceleration of air parcels. This term is associated with storms having high precipitation rates. Comparing the effects of water loading to those associated with buoyancy, if a parcel has a liquid water mixing ratio of 1.0 g kg−1, this is roughly equivalent to about 0.3 K of negative buoyancy; the latter is a large (but not extreme) value. Therefore, in general terms, negative buoyancy is typically the major contributor to downdrafts.[16]

Negative vertical motion associated only with buoyancy edit

Using pure "parcel theory" results in a prediction of the maximum downdraft of

 

where NAPE is the negative available potential energy,

 

and where LFS denotes the level of free sink for a descending parcel and SFC denotes the surface. This means that the maximum downward motion is associated with the integrated negative buoyancy. Even a relatively modest negative buoyancy can result in a substantial downdraft if it is maintained over a relatively large depth. A downward speed of 25 m/s (56 mph; 90 km/h) results from the relatively modest NAPE value of 312.5 m2 s−2. To a first approximation, the maximum gust is roughly equal to the maximum downdraft speed.[16]

Heat bursts edit

A special, and much rarer, kind of downburst is a heat burst, which results from precipitation-evaporated air compressionally heating as it descends from very high altitude, usually on the backside of a dying squall line or outflow boundary.[17] Heat bursts are chiefly a nocturnal occurrence, can produce winds over 160 km/h (100 mph), are characterized by exceptionally dry air, can suddenly raise the surface temperature to 38 °C (100 °F) or more, and sometimes persist for several hours.

Danger to aviation edit

 
A series of photographs of the surface curl soon after a microburst impacted the surface

Downbursts, particularly microbursts, are exceedingly dangerous to aircraft which are taking off or landing due to the strong vertical wind shear caused by these events. Several fatal crashes are attributed to downbursts.[18]

The following are some fatal crashes and/or aircraft incidents that have been attributed to microbursts in the vicinity of airports:

A microburst often causes aircraft to crash when they are attempting to land or shortly after takeoff (American Airlines Flight 63 and Delta Air Lines Flight 318 are a notable exception). The microburst is an extremely powerful gust of air that, once hitting the surface, spreads in all directions. As the aircraft is coming in to land, the pilots try to slow the plane to an appropriate speed. When the microburst hits, the pilots will see a large spike in their airspeed, caused by the force of the headwind created by the microburst. A pilot inexperienced with microbursts would try to decrease the speed. The plane would then travel through the microburst, and fly into the tailwind, causing a sudden decrease in the amount of air flowing across the wings. The decrease in airflow over the wings of the aircraft causes a drop in the amount of lift produced. This decrease in lift combined with a strong downward flow of air can cause the thrust required to remain at altitude to exceed what is available, thus causing the aircraft to stall.[18] If the plane is at a low altitude shortly after takeoff or during landing, it will not have sufficient altitude to recover.

The strongest microburst recorded thus far occurred at Andrews Field, Maryland on 1 August 1983, with wind speeds reaching 240.5 km/h (149.4 mph).[43]

Danger to buildings edit

  • On June 21, 2023, a severe thunderstorm in the Greater Houston area resulted in a powerful downburst. The storm was part of a larger tornado outbreak sequence that occurred from June 20-26, 2023. A record-breaking wind gust of 97 mph (156 km/h) was observed at George Bush Intercontinental Airport, surpassing the previous record of 82 mph (132 km/h) recorded during Hurricane Ike in 2008.[44] The aftermath left approximately 324,000 customers without power and caused extensive damage to CenterPoint Energy's equipment and infrastructure.[45] The storm caused significant damage to buildings, with at least 243 homes damaged.[46] The storm was strong enough to flip a small plane and push another off the tarmac at Hooks Airport in northwest Harris County.[47][48]
  • On 21 May 2022, a particularly intense downburst was responsible for damage in Ottawa, Ontario, Canada. Maximum wind speeds reaching 190 km/h (120 mph) were surveyed and analyzed by the Northern Tornados Project, in an area measuring approximately 36 km (22 mi) long and 5 km (3 mi) wide.[49] 10 people were killed and many communities experienced significant damage and power outages spanning days as a result of the derecho that moved across Ontario and Quebec.[50] It was one of Canada’s most destructive wind storms in its history, with over $875 million in damages across both provinces.[51]
 
Strong microburst winds flip a several-ton shipping container up the side of a hill, Vaughan, Ontario, Canada
  • On 31 March 2019, a very destructive downburst cluster with characteristics of a small derecho[clarification needed], but too small to satisfy the criteria, impacted across a 33 km (21 mi) wide and 45 km (28 mi) long swath in the Bara and Parsa Districts, Nepal. Occurring at an elevation of 83 to 109 m (270 to 360 ft) amsl around 18:45 local time, the 30-45 min duration winds flattened many and severely damaged numerous buildings, leading to 28 deaths and hundreds of injuries.[52]
  • On 15 May 2018, an extremely powerful front moved through the northeastern United States, specifically New York and Connecticut, causing significant damage. Nearly a half million people lost power and 5 people were killed. Winds were recorded in excess of 100 mph (160 km/h) and several tornadoes and macrobursts were confirmed by the NWS.
  • On 3 April 2018, a wet microburst struck William P. Hobby Airport, Texas at 11:53 PM, causing an aircraft hangar to partially collapse. Six business jets (four stored in the hangar and two outside) were damaged. A severe thunderstorm warning was issued just seconds before the microburst struck.
  • On 23 May 2017, a wet microburst struck Sealy, Texas with 80 to 100 mph (130 to 160 km/h) winds knocking down trees and power lines. Significant damage to structures was reported across Sealy. Twenty students were slightly injured by flying debris while attending a function at Sealy High School.
  • On 9 August 2016, a wet microburst struck the city of Cleveland Heights, Ohio, an eastern suburb of Cleveland.[53][54] The storm developed very quickly. Thunderstorms developed west of Cleveland at 9 PM, and the National Weather Service issued a severe thunderstorm warning at 9:55 PM. The storm had passed over Cuyahoga County by 10:20 PM.[55] Lightning struck 10 times per minute over Cleveland Heights.[55] and 80 mph (130 km/h) winds knocked down hundreds of trees and utility poles.[54][56] More than 45,000 people lost power, with damage so severe that nearly 6,000 homes remained without power two days later.[56]
  • On 22 July 2016, a wet microburst hit portions of Kent and Providence Counties in Rhode Island, causing wind damage in the cities of Cranston, Rhode Island and West Warwick, Rhode Island. Numerous fallen trees were reported, as well as downed powerlines and minimal property damage. Thousands of people were without power for several days, even as long as over 4 days. The storm occurred late at night, and no injuries were reported.
  • On 23 June 2015, a macroburst hit portions of Gloucester and Camden Counties in New Jersey causing widespread damage mostly due to falling trees. Electrical utilities were affected for several days causing protracted traffic signal disruption and closed businesses.
  • On 23 August 2014, a dry microburst hit Mesa, Arizona. It ripped the roof off of half a building and a shed, nearly damaging the surrounding buildings. No serious injuries were reported.
  • On 21 December 2013 a wet microburst hit Brunswick, Ohio. The roof was ripped off of a local business; the debris damaged several houses and cars near the business. Due to the time, between 1 am and 2 am, there were no injuries.
  • On 9 July 2012, a wet microburst hit an area of Spotsylvania County, Virginia near the border of the city of Fredericksburg, causing severe damage to two buildings. One of the buildings was a children's cheerleading center. Two serious injuries were reported.
  • On 22 June 2012, a wet microburst hit the town of Bladensburg, Maryland, causing severe damage to trees, apartment buildings, and local roads. The storm caused an outage in which 40,000 customers lost power.
  • On 8 September 2011, at 5:01 PM, a dry microburst hit Nellis Air Force Base, Nevada causing several aircraft shelters to collapse. Multiple aircraft were damaged and eight people were injured.[57]
  • On 18 August 2011, a wet microburst hit the musical festival Pukkelpop in Hasselt, causing severe localized damage. Five people were killed and at least 140 people were injured. Later research showed that the wind reached speeds of 170 km/h (110 mph).
  • On 22 September 2010, in the Hegewisch neighborhood of Chicago, a wet microburst hit, causing severe localized damage and localized power outages, including fallen-tree impacts into at least four homes. No fatalities were reported.[58]
  • On 16 September 2010, just after 5:30 PM, a wet macroburst with winds of 125 mph (200 km/h) hit parts of Central Queens in New York City, causing extensive damage to trees, buildings, and vehicles in an area 8 miles long and 5 miles wide. Approximately 3,000 trees were knocked down by some reports. There was one fatality when a tree fell onto a car on the Grand Central Parkway.[59][60]
  • On 24 June 2010, shortly after 4:30 PM, a wet microburst hit the city of Charlottesville, Virginia. Field reports and damage assessments show that Charlottesville experienced numerous downbursts during the storm, with wind estimates at over 75 mph (120 km/h). In a matter of minutes, trees and downed power lines littered the roadways. A number of houses were hit by trees. Immediately after the storm, up to 60,000 Dominion Power customers in Charlottesville and surrounding Albemarle County were without power.[61]
  • On 11 June 2010, around 3:00 AM, a wet microburst hit a neighborhood in southwestern Sioux Falls, South Dakota. It caused major damage to four homes, all of which were occupied. No injuries were reported. Roofs were blown off of garages and walls were flattened by the estimated 100 mph (160 km/h) winds. The cost of repairs was thought to be $500,000 or more.[62]
  • On 2 May 2009, the lightweight steel and mesh building in Irving, Texas used for practice by the Dallas Cowboys football team was flattened by a microburst, according to the National Weather Service.[63]
  • On 12 March 2006, a microburst hit Lawrence, Kansas. 60 percent of the University of Kansas campus buildings sustained some form of damage from the storm. Preliminary estimates put the cost of repairs at between $6 million and $7 million.[64]
  • On 13 May 1989, a microburst with winds over 95 mph (150 km/h) hit Fort Hood, Texas. Over 200 U.S. Army helicopters were damaged. The storm damaged at least 20 percent of the fort's buildings, forcing 25 military families from their quarters. In a preliminary damage estimate, the Army said repairs to almost 200 helicopters would cost $585 million and repairs to buildings and other facilities about $15 million.[65]
  • On May 9, 1980, a microburst at the leading edge of an advancing cold front struck the 606 ft (185 m) freighter MV Summit Venture just as it was about to pass through the narrow channel under the Sunshine Skyway Bridge over Tampa Bay. Sudden torrential rain cut visibility to zero and straight-line winds estimated at over 70 mph (110 km/h) pushed the ship into a support pier, causing the catastrophic collapse of the southbound span and 35 deaths as several private vehicles and a Greyhound Bus plummeted 150 ft (46 m) into the water..[66]
  • On 4 July 1977, the Independence Day Derecho of 1977 formed over west-central Minnesota. As the derecho moved east-southeast, it became very intense over central Minnesota around midday. From that time through the afternoon the system produced winds of 80 to more than 100 mph (160 km/h), with areas of extreme damage from central Minnesota into northern Wisconsin. The derecho continued rapidly southeast before finally weakening over northern Ohio.

See also edit

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Bibliography edit

External links edit

downburst, album, brainstorm, album, networking, phenomenon, micro, bursting, networking, meteorology, downburst, strong, downward, outward, gushing, wind, system, that, emanates, from, point, source, above, blows, radially, that, straight, lines, directions, . For the album by Brainstorm see Downburst album For the networking phenomenon see Micro bursting networking In meteorology a downburst is a strong downward and outward gushing wind system that emanates from a point source above and blows radially that is in straight lines in all directions from the area of impact at surface level Capable of producing damaging winds it may sometimes be confused with a tornado where high velocity winds circle a central area and air moves inward and upward These usually last for seconds to minutes Downbursts are particularly strong downdrafts within thunderstorms or deep moist convection as sometimes downbursts emanate from cumulonimbus or even cumulus congestus clouds that are not producing lightning Illustration of a microburst The air moves in a downward motion until it hits the surface It then spreads outward in all directions The wind regime in a microburst is opposite to that of a tornado Downbursts are most often created by an area of significantly precipitation cooled air that after reaching the surface subsiding spreads out in all directions producing strong winds Dry downbursts are associated with thunderstorms that exhibit very little rain while wet downbursts are created by thunderstorms with significant amounts of precipitation 1 Microbursts and macrobursts are downbursts at very small and larger scales respectively A rare variety of dry downburst the heat burst is created by vertical currents on the backside of old outflow boundaries and squall lines where rainfall is lacking Heat bursts generate significantly higher temperatures due to the lack of rain cooled air in their formation and compressional heating during descent Downbursts create vertical wind shear which is dangerous to aviation especially during landing or takeoff Several fatal and historic crashes in past decades are attributed to the phenomenon and flight crew training goes to great lengths on how to properly recognize and recover from a downburst wind shear event wind shear recovery among other adverse weather events are standard topics across the world in flight simulator training that flight crews receive and must successfully complete Detection and nowcasting technology was also implemented in much of the world and particularly around major airports which in many cases actually have wind shear detection equipment on the field This detection equipment helps air traffic controllers and pilots make decisions on the safety and feasibility of operating on or in the vicinity of the airport during storms 2 Contents 1 Definition 1 1 Dry microbursts 1 2 Wet microbursts 1 3 Straight line winds 2 Formation 3 Development stages of microbursts 4 Physical processes of dry and wet microbursts 4 1 Basic physical processes using simplified buoyancy equations 4 2 Negative vertical motion associated only with buoyancy 5 Heat bursts 6 Danger to aviation 7 Danger to buildings 8 See also 9 References 10 Bibliography 11 External linksDefinition edit nbsp Downburst damages in a straight lineA downburst is created by a column of sinking air that after hitting the surface spreads out in all directions and is capable of producing damaging straight line winds of over 240 km h 150 mph often producing damage similar to but distinguishable from that caused by tornadoes 1 Downburst damage radiates from a central point as the descending column spreads out when hitting the surface whereas tornado damage tends towards convergent damage consistent with rotating winds To differentiate between tornado damage and damage from a downburst the term straight line winds is applied to damage from microbursts Downbursts in air that is precipitation free or contains virga are known as dry downbursts 3 those accompanied with precipitation are known as wet downbursts These generally are formed by precipitation cooled air rushing to the surface but they perhaps also could be powered by strong winds aloft being deflected toward the surface by dynamical processes in a thunderstorm see rear flank downdraft citation needed Most downbursts are less than 4 km 2 5 mi in extent these are called microbursts 4 Downbursts larger than 4 km 2 5 mi in extent are sometimes called macrobursts 4 Downbursts can occur over large areas In the extreme case a series of continuing downbursts results in a derecho which covers huge areas of more than 320 km 200 mi wide and over 1 600 km 1 000 mi long persisting for 12 hours or more and which is associated with some of the most intense straight line winds 5 The term microburst was defined by mesoscale meteorology expert Ted Fujita as affecting an area 4 km 2 5 mi in diameter or less distinguishing them as a type of downburst and apart from common wind shear which can encompass greater areas 6 Fujita also coined the term macroburst for downbursts larger than 4 km 2 5 mi 7 Dry microbursts edit nbsp Dry microburst schematicWhen rain falls below the cloud base or is mixed with dry air it begins to evaporate and this evaporation process cools the air The denser cool air descends and accelerates as it approaches the surface When the cool air approaches the surface it spreads out in all directions High winds spread out in this type of pattern showing little or no curvature are known as straight line winds 8 Dry microbursts are typically produced by high based thunderstorms that contain little to no surface rainfall They occur in environments characterized by a thermodynamic profile exhibiting an inverted V at thermal and moisture profile as viewed on a Skew T log P thermodynamic diagram Wakimoto 1985 developed a conceptual model over the High Plains of the United States of a dry microburst environment that comprised three important variables mid level moisture cloud base in the mid troposphere and low surface relative humidity These conditions evaporate the moisture from the air as it falls cooling the air and making it fall faster because it is more dense Wet microbursts edit nbsp A wet microburstWet microbursts are downbursts accompanied by significant precipitation at the surface 9 These downbursts rely more on the drag of precipitation for downward acceleration of parcels as well as the negative buoyancy which tend to drive dry microbursts As a result higher mixing ratios are necessary for these downbursts to form hence the name wet microbursts Melting of ice particularly hail appears to play an important role in downburst formation Wakimoto and Bringi 1988 especially in the lowest 1 km 0 6 mi above surface level Proctor 1989 These factors among others make forecasting wet microbursts difficult Characteristic Dry Microburst Wet MicroburstLocation of highest probability within the United States Midwest West SoutheastPrecipitation Little or none Moderate or heavyCloud bases As high as 500 hPa mb As high as 850 hPa mb Features below cloud base Virga Precipitation shaftPrimary catalyst Evaporative cooling Precipitation loading and evaporative coolingEnvironment below cloud base Deep dry layer low relative humidity dry adiabatic lapse rate Shallow dry layer high relative humidity moist adiabatic lapse rateStraight line winds edit See also Derecho Straight line winds also known as plough winds thundergusts and hurricanes of the prairie are very strong winds that can produce damage demonstrating a lack of the rotational damage pattern associated with tornadoes 10 Straight line winds are common with the gust front of a thunderstorm or originate with a downburst from a thunderstorm These events can cause considerable damage even in the absence of a tornado The winds can gust to 58 m s 130 mph 11 and winds of 26 m s 58 mph or more can last for more than twenty minutes 12 In the United States such straight line wind events are most common during the spring when instability is highest and weather fronts routinely cross the country citation needed Straight line wind events in the form of derechos can take place throughout the eastern half of the U S 13 Straight line winds may be damaging to marine interests Small ships cutters and sailboats are at risk from this meteorological phenomenon citation needed Formation editThe formation of a downburst starts with hail or large raindrops falling through drier air Hailstones melt and raindrops evaporate pulling latent heat from surrounding air and cooling it considerably Cooler air has a higher density than the warmer air around it so it sinks to the surface As the cold air hits the ground or water it spreads out and a mesoscale front can be observed as a gust front Areas under and immediately adjacent to the downburst are the areas which receive the highest winds and rainfall if any is present Also because the rain cooled air is descending from the middle troposphere a significant drop in temperatures is noticed Due to interaction with the surface the downburst quickly loses strength as it fans out and forms the distinctive curl shape that is commonly seen at the periphery of the microburst see image Downbursts usually last only a few minutes and then dissipate except in the case of squall lines and derecho events However despite their short lifespan microbursts are a serious hazard to aviation and property and can result in substantial damage to the area Downbursts go through three stages in their cycle the downburst outburst and cushion stages 14 Development stages of microbursts editThe evolution of microbursts is broken down into three stages the contact stage the outburst stage and the cushion stage 15 A downburst initially develops as the downdraft begins its descent from the cloud base The downdraft accelerates and within minutes reaches the surface contact stage During the outburst stage the wind curls as the cold air of the downburst moves away from the point of impact with the surface During the cushion stage winds about the curl continue to accelerate while the winds at the surface slow due to friction nbsp nbsp nbsp nbsp Downburst on a weather radar On a weather radar Doppler display a downburst is seen as a couplet of radial winds in the outburst and cushion stages The rightmost image shows such a display from the ARMOR Doppler Weather Radar in Huntsville Alabama in 2012 The radar is on the right side of the image and the downburst is along the line separating the velocity towards the radar green and the one moving away red Physical processes of dry and wet microbursts edit nbsp Basic physical processes using simplified buoyancy equations edit Start by using the vertical momentum equation d w d t 1 r p z g displaystyle dw over dt 1 over rho partial p over partial z g nbsp By decomposing the variables into a basic state and a perturbation defining the basic states and using the ideal gas law p r R T v displaystyle p rho RT v nbsp then the equation can be written in the form B r r g g T v T v T v displaystyle B equiv rho prime over bar rho g g T v prime bar T v over bar T v nbsp where B is buoyancy The virtual temperature correction usually is rather small and to a good approximation it can be ignored when computing buoyancy Finally the effects of precipitation loading on the vertical motion are parametrized by including a term that decreases buoyancy as the liquid water mixing ratio ℓ displaystyle ell nbsp increases leading to the final form of the parcel s momentum equation d w d t 1 r p z B g ℓ displaystyle dw prime over dt 1 over bar rho partial p prime over partial z B g ell nbsp The first term is the effect of perturbation pressure gradients on vertical motion In some storms this term has a large effect on updrafts Rotunno and Klemp 1982 but there is not much reason to believe it has much of an impact on downdrafts at least to a first approximation and therefore will be ignored The second term is the effect of buoyancy on vertical motion Clearly in the case of microbursts one expects to find that B is negative meaning the parcel is cooler than its environment This cooling typically takes place as a result of phase changes evaporation melting and sublimation Precipitation particles that are small but are in great quantity promote a maximum contribution to cooling and hence to creation of negative buoyancy The major contribution to this process is from evaporation The last term is the effect of water loading Whereas evaporation is promoted by large numbers of small droplets it only requires a few large drops to contribute substantially to the downward acceleration of air parcels This term is associated with storms having high precipitation rates Comparing the effects of water loading to those associated with buoyancy if a parcel has a liquid water mixing ratio of 1 0 g kg 1 this is roughly equivalent to about 0 3 K of negative buoyancy the latter is a large but not extreme value Therefore in general terms negative buoyancy is typically the major contributor to downdrafts 16 Negative vertical motion associated only with buoyancy edit Using pure parcel theory results in a prediction of the maximum downdraft of w m a x 2 NAPE displaystyle w rm max sqrt 2 times hbox NAPE nbsp where NAPE is the negative available potential energy NAPE S F C L F S B d z displaystyle hbox NAPE int rm SFC rm LFS B dz nbsp and where LFS denotes the level of free sink for a descending parcel and SFC denotes the surface This means that the maximum downward motion is associated with the integrated negative buoyancy Even a relatively modest negative buoyancy can result in a substantial downdraft if it is maintained over a relatively large depth A downward speed of 25 m s 56 mph 90 km h results from the relatively modest NAPE value of 312 5 m2 s 2 To a first approximation the maximum gust is roughly equal to the maximum downdraft speed 16 Heat bursts editMain article Heat burst A special and much rarer kind of downburst is a heat burst which results from precipitation evaporated air compressionally heating as it descends from very high altitude usually on the backside of a dying squall line or outflow boundary 17 Heat bursts are chiefly a nocturnal occurrence can produce winds over 160 km h 100 mph are characterized by exceptionally dry air can suddenly raise the surface temperature to 38 C 100 F or more and sometimes persist for several hours Danger to aviation editFurther information Wind shear and Cumulonimbus and aviation nbsp A series of photographs of the surface curl soon after a microburst impacted the surfaceDownbursts particularly microbursts are exceedingly dangerous to aircraft which are taking off or landing due to the strong vertical wind shear caused by these events Several fatal crashes are attributed to downbursts 18 The following are some fatal crashes and or aircraft incidents that have been attributed to microbursts in the vicinity of airports This list is incomplete you can help by adding missing items August 2022 1950 Air France multiple Douglas DC 4 accidents Douglas DC 4 F BBDE and F BBDM Bahrain International Airport 12 and 14 June 1950 19 1956 Kano Airport BOAC Argonaut crash Canadair C 4 Argonaut G ALHE Kano Airport 24 June 1956 20 Malev Flight 731 Ilyushin Il 18 HA MOC Copenhagen Airport 28 August 1971 21 Ozark Air Lines Flight 809 Fairchild F 27 N4215 St Louis International Airport 23 July 1973 22 Pan Am Flight 806 Boeing 707 N454PA Pago Pago International Airport 30 January 1974 23 Eastern Air Lines Flight 66 Boeing 727 N8845E John F Kennedy International Airport 24 June 1975 18 Continental Airlines Flight 426 Boeing 727 N88777 Stapleton International Airport 7 August 1975 24 Allegheny Airlines Flight 121 Douglas DC 9 N994VJ Philadelphia International Airport 23 June 1976 25 Continental Airlines Flight 63 Boeing 727 N32725 Tucson International Airport 3 June 1977 26 Aeroflot Flight 4225 Tupolev Tu 154 CCCP 85355 Almaty International Airport 8 July 1980 27 Pan Am Flight 759 Boeing 727 N4737 New Orleans International Airport 9 July 1982 18 USAir Flight 183 McDonnell Douglas DC 9 N964VJ Detroit Metropolitan Airport 13 June 1984 28 United Airlines Flight 663 Boeing 727 N7647U Stapleton International Airport 31 May 1984 29 Delta Air Lines Flight 191 Lockheed L 1011 TriStar N726DA Dallas Fort Worth International Airport 2 August 1985 18 Mandala Airlines Flight 660 Vickers Viscount 816 PK RVU Pattimura International Airport 24 July 1992 30 Martinair Flight 495 McDonnell Douglas DC 10 PH MBN Faro Airport 21 December 1992 31 USAir Flight 1016 McDonnell Douglas DC 9 N954VJ Charlotte Douglas International Airport 2 July 1994 32 Wuhan Airlines Flight 343 Xian Y 7 B 3479 Wuhan Wangjiadun Airport 22 June 2000 33 Iberia Flight 1456 Airbus A320 EC HKJ Bilbao Airport 7 February 2001 34 Goodyear Blimp GZ 20 N1A Stars and Stripes Pompano Beach Airpark 16 June 2005 35 36 Sosoliso Airlines Flight 1145 McDonnell Douglas DC 9 5N BFD Port Harcourt International Airport 10 December 2005 37 ADC Airlines Flight 053 Boeing 737 5N BFK Nnamdi Azikiwe International Airport 29 October 2006 38 Georgian Airways Flight 834 Bombardier CRJ100 4L GAE Kinshasa Airport 4 April 2011 39 Bhoja Air Flight 213 Boeing 737 AP BKC Islamabad International Airport 20 April 2012 40 Aeromexico Connect Flight 2431 Embraer 190 XA GAL Durango International Airport 31 July 2018 41 UTair Flight 579 Boeing 737 VQ BJI Sochi International Airport 1 September 2018 42 A microburst often causes aircraft to crash when they are attempting to land or shortly after takeoff American Airlines Flight 63 and Delta Air Lines Flight 318 are a notable exception The microburst is an extremely powerful gust of air that once hitting the surface spreads in all directions As the aircraft is coming in to land the pilots try to slow the plane to an appropriate speed When the microburst hits the pilots will see a large spike in their airspeed caused by the force of the headwind created by the microburst A pilot inexperienced with microbursts would try to decrease the speed The plane would then travel through the microburst and fly into the tailwind causing a sudden decrease in the amount of air flowing across the wings The decrease in airflow over the wings of the aircraft causes a drop in the amount of lift produced This decrease in lift combined with a strong downward flow of air can cause the thrust required to remain at altitude to exceed what is available thus causing the aircraft to stall 18 If the plane is at a low altitude shortly after takeoff or during landing it will not have sufficient altitude to recover The strongest microburst recorded thus far occurred at Andrews Field Maryland on 1 August 1983 with wind speeds reaching 240 5 km h 149 4 mph 43 Danger to buildings editOn June 21 2023 a severe thunderstorm in the Greater Houston area resulted in a powerful downburst The storm was part of a larger tornado outbreak sequence that occurred from June 20 26 2023 A record breaking wind gust of 97 mph 156 km h was observed at George Bush Intercontinental Airport surpassing the previous record of 82 mph 132 km h recorded during Hurricane Ike in 2008 44 The aftermath left approximately 324 000 customers without power and caused extensive damage to CenterPoint Energy s equipment and infrastructure 45 The storm caused significant damage to buildings with at least 243 homes damaged 46 The storm was strong enough to flip a small plane and push another off the tarmac at Hooks Airport in northwest Harris County 47 48 On 21 May 2022 a particularly intense downburst was responsible for damage in Ottawa Ontario Canada Maximum wind speeds reaching 190 km h 120 mph were surveyed and analyzed by the Northern Tornados Project in an area measuring approximately 36 km 22 mi long and 5 km 3 mi wide 49 10 people were killed and many communities experienced significant damage and power outages spanning days as a result of the derecho that moved across Ontario and Quebec 50 It was one of Canada s most destructive wind storms in its history with over 875 million in damages across both provinces 51 nbsp Strong microburst winds flip a several ton shipping container up the side of a hill Vaughan Ontario CanadaOn 31 March 2019 a very destructive downburst cluster with characteristics of a small derecho clarification needed but too small to satisfy the criteria impacted across a 33 km 21 mi wide and 45 km 28 mi long swath in the Bara and Parsa Districts Nepal Occurring at an elevation of 83 to 109 m 270 to 360 ft amsl around 18 45 local time the 30 45 min duration winds flattened many and severely damaged numerous buildings leading to 28 deaths and hundreds of injuries 52 On 15 May 2018 an extremely powerful front moved through the northeastern United States specifically New York and Connecticut causing significant damage Nearly a half million people lost power and 5 people were killed Winds were recorded in excess of 100 mph 160 km h and several tornadoes and macrobursts were confirmed by the NWS On 3 April 2018 a wet microburst struck William P Hobby Airport Texas at 11 53 PM causing an aircraft hangar to partially collapse Six business jets four stored in the hangar and two outside were damaged A severe thunderstorm warning was issued just seconds before the microburst struck On 23 May 2017 a wet microburst struck Sealy Texas with 80 to 100 mph 130 to 160 km h winds knocking down trees and power lines Significant damage to structures was reported across Sealy Twenty students were slightly injured by flying debris while attending a function at Sealy High School On 9 August 2016 a wet microburst struck the city of Cleveland Heights Ohio an eastern suburb of Cleveland 53 54 The storm developed very quickly Thunderstorms developed west of Cleveland at 9 PM and the National Weather Service issued a severe thunderstorm warning at 9 55 PM The storm had passed over Cuyahoga County by 10 20 PM 55 Lightning struck 10 times per minute over Cleveland Heights 55 and 80 mph 130 km h winds knocked down hundreds of trees and utility poles 54 56 More than 45 000 people lost power with damage so severe that nearly 6 000 homes remained without power two days later 56 On 22 July 2016 a wet microburst hit portions of Kent and Providence Counties in Rhode Island causing wind damage in the cities of Cranston Rhode Island and West Warwick Rhode Island Numerous fallen trees were reported as well as downed powerlines and minimal property damage Thousands of people were without power for several days even as long as over 4 days The storm occurred late at night and no injuries were reported On 23 June 2015 a macroburst hit portions of Gloucester and Camden Counties in New Jersey causing widespread damage mostly due to falling trees Electrical utilities were affected for several days causing protracted traffic signal disruption and closed businesses On 23 August 2014 a dry microburst hit Mesa Arizona It ripped the roof off of half a building and a shed nearly damaging the surrounding buildings No serious injuries were reported On 21 December 2013 a wet microburst hit Brunswick Ohio The roof was ripped off of a local business the debris damaged several houses and cars near the business Due to the time between 1 am and 2 am there were no injuries On 9 July 2012 a wet microburst hit an area of Spotsylvania County Virginia near the border of the city of Fredericksburg causing severe damage to two buildings One of the buildings was a children s cheerleading center Two serious injuries were reported On 22 June 2012 a wet microburst hit the town of Bladensburg Maryland causing severe damage to trees apartment buildings and local roads The storm caused an outage in which 40 000 customers lost power On 8 September 2011 at 5 01 PM a dry microburst hit Nellis Air Force Base Nevada causing several aircraft shelters to collapse Multiple aircraft were damaged and eight people were injured 57 On 18 August 2011 a wet microburst hit the musical festival Pukkelpop in Hasselt causing severe localized damage Five people were killed and at least 140 people were injured Later research showed that the wind reached speeds of 170 km h 110 mph On 22 September 2010 in the Hegewisch neighborhood of Chicago a wet microburst hit causing severe localized damage and localized power outages including fallen tree impacts into at least four homes No fatalities were reported 58 On 16 September 2010 just after 5 30 PM a wet macroburst with winds of 125 mph 200 km h hit parts of Central Queens in New York City causing extensive damage to trees buildings and vehicles in an area 8 miles long and 5 miles wide Approximately 3 000 trees were knocked down by some reports There was one fatality when a tree fell onto a car on the Grand Central Parkway 59 60 On 24 June 2010 shortly after 4 30 PM a wet microburst hit the city of Charlottesville Virginia Field reports and damage assessments show that Charlottesville experienced numerous downbursts during the storm with wind estimates at over 75 mph 120 km h In a matter of minutes trees and downed power lines littered the roadways A number of houses were hit by trees Immediately after the storm up to 60 000 Dominion Power customers in Charlottesville and surrounding Albemarle County were without power 61 On 11 June 2010 around 3 00 AM a wet microburst hit a neighborhood in southwestern Sioux Falls South Dakota It caused major damage to four homes all of which were occupied No injuries were reported Roofs were blown off of garages and walls were flattened by the estimated 100 mph 160 km h winds The cost of repairs was thought to be 500 000 or more 62 On 2 May 2009 the lightweight steel and mesh building in Irving Texas used for practice by the Dallas Cowboys football team was flattened by a microburst according to the National Weather Service 63 On 12 March 2006 a microburst hit Lawrence Kansas 60 percent of the University of Kansas campus buildings sustained some form of damage from the storm Preliminary estimates put the cost of repairs at between 6 million and 7 million 64 On 13 May 1989 a microburst with winds over 95 mph 150 km h hit Fort Hood Texas Over 200 U S Army helicopters were damaged The storm damaged at least 20 percent of the fort s buildings forcing 25 military families from their quarters In a preliminary damage estimate the Army said repairs to almost 200 helicopters would cost 585 million and repairs to buildings and other facilities about 15 million 65 On May 9 1980 a microburst at the leading edge of an advancing cold front struck the 606 ft 185 m freighter MV Summit Venture just as it was about to pass through the narrow channel under the Sunshine Skyway Bridge over Tampa Bay Sudden torrential rain cut visibility to zero and straight line winds estimated at over 70 mph 110 km h pushed the ship into a support pier causing the catastrophic collapse of the southbound span and 35 deaths as several private vehicles and a Greyhound Bus plummeted 150 ft 46 m into the water 66 On 4 July 1977 the Independence Day Derecho of 1977 formed over west central Minnesota As the derecho moved east southeast it became very intense over central Minnesota around midday From that time through the afternoon the system produced winds of 80 to more than 100 mph 160 km h with areas of extreme damage from central Minnesota into northern Wisconsin The derecho continued rapidly southeast before finally weakening over northern Ohio See also editBow echo Haboob Line echo wave pattern LEWP List of derecho events List of microbursts Low level windshear alert system LLWAS Mesovortex Planetary boundary layer PBL Rear inflow jet RIJ Squall Vertical draft WindthrowReferences edit a b US Department of Commerce NOAA Downbursts www weather gov Retrieved 15 June 2022 Downbursts PennState Retrieved 15 June 2022 Fernando Caracena Ronald L Holle and Charles A Doswell III Microbursts A Handbook for Visual Identification Retrieved on 9 July 2008 a b Glossary of Meteorology Macroburst Retrieved on 30 July 2008 Peter S Parke and Norvan J Larson Boundary Waters Windstorm Retrieved on 30 July 2008 Glossary of Meteorology Microburst Archived 2008 12 12 at the Wayback Machine Retrieved on 2008 07 30 Glossary of Meteorology Macroburst Retrieved on 2008 07 30 Glossary of Meteorology Straight line wind Archived 2008 04 15 at the Wayback Machine Retrieved on 2008 08 01 Fujita T T 1985 The Downburst microburst and macroburst SMRP Research Paper 210 122 pp Glossary of Meteorology Straight line wind Archived 15 April 2008 at the Wayback Machine Retrieved on 1 August 2008 Facts About Derechos Very Damaging Windstorms The Corn Belt Derecho of 29 June 1998 Facts About Derechos Very Damaging Windstorms What is a Microburst National Weather Service n d Retrieved 10 March 2018 University of Illinois Urbana Champaign Microbursts Retrieved on 2008 08 04 a b Charles A Doswell III Extreme Convective Windstorms Current Understanding and Research Retrieved on 2008 08 04 Oklahoma heat burst sends temperatures soaring USA Today 1999 07 08 8 July 1999 Archived from the original on 25 December 1996 Retrieved 9 May 2007 a b c d e NASA Langley Air Force Base Making the Skies Safer From Windshear Archived 2010 03 29 at the Wayback Machine Retrieved on 2006 10 22 St Christophers Cathedral 6 July 2011 Archived from the original on 6 July 2011 Retrieved 5 August 2022 Ranter Harro ASN Aircraft accident Canadair C 4 Argonaut G ALHE Kano International Airport KAN aviation safety net Retrieved 5 August 2022 Katasztrofa Koppenhagaban a gyilkos learamlas iho hu in Hungarian Retrieved 5 August 2022 Ranter Harro ASN Aircraft accident Fairchild FH 227B N4215 Saint Louis Lambert International Airport MO STL aviation safety net Retrieved 12 September 2022 Ranter Harro ASN Aircraft accident Boeing 707 321B N454PA Pago Pago International Airport PPG aviation safety net Retrieved 12 September 2022 Ranter Harro ASN Aircraft accident Boeing 727 224 N88777 Denver Stapleton International Airport CO DEN aviation safety net Retrieved 13 September 2022 Ranter Harro ASN Aircraft accident McDonnell Douglas DC 9 31 N994VJ Philadelphia International Airport PA PHL aviation safety net Retrieved 13 September 2022 Ranter Harro ASN Aircraft accident Boeing 727 224 Advanced N32725 Tucson International Airport AZ TUS aviation safety net Retrieved 13 September 2022 Ranter Harro ASN Aircraft accident Tupolev Tu 154B 2 CCCP 85355 Alma Ata Airport ALA aviation safety net Retrieved 12 September 2022 Runway excursion USAir Inc Flight 183 McDonnell Douglas DC9 31 N964VJ Detroit Metropolitan Airport Detroit Michigan June 13 1983 PDF Collision with localizer on takeoff United Airlines Flight 663 Boeing 727 PDF Accident Database Accident Synopsis 07241992 archive ph 20 July 2012 Retrieved 5 August 2022 Aviation Safety Network Damage Report Retrieved on 2008 08 01 Ranter Harro ASN Aircraft accident McDonnell Douglas DC 9 31 N954VJ Charlotte Douglas Airport NC CLT aviation safety net Retrieved 10 May 2022 Ranter Harro ASN Aircraft accident Xian Yunshuji Y 7 100C B 3479 Wuhan www aviation safety net Retrieved 21 July 2022 Ranter Harro ASN Aircraft accident Airbus A320 214 EC HKJ Bilbao Airport BIO aviation safety net Retrieved 12 September 2022 ATL05CA100 11 October 2006 Archived from the original on 11 October 2006 Retrieved 10 May 2022 Blimp Crash Lands In Florida www cbsnews com Retrieved 12 September 2022 Ranter Harro ASN Aircraft accident McDonnell Douglas DC 9 32 5N BFD Port Harcourt Airport PHC aviation safety net Retrieved 12 September 2022 Ranter Harro ASN Aircraft accident Boeing 737 2B7 5N BFK Abuja International Airport ABV aviation safety net Retrieved 12 September 2022 Ranter Harro ASN Aircraft accident Canadair CL 600 2B19 Regional Jet CRJ 100ER 4L GAE Kinshasa N Djili Airport FIH aviation safety net Retrieved 12 September 2022 Ranter Harro ASN Aircraft accident Boeing 737 236A AP BKC Islamabad Benazir Bhutto International Airport ISB aviation safety net Retrieved 10 May 2022 Ranter Harro ASN Aircraft accident Embraer ERJ 190AR XA GAL Durango Guadalupe Victoria Airport DGO www aviation safety net Retrieved 10 May 2022 Ranter Harro ASN Aircraft accident Boeing 737 8AS WL VQ BJI Adler Sochi Airport AER aviation safety net Retrieved 1 November 2022 Strongest microburst Guinness World Records Archived from the original on 6 January 2022 Retrieved 6 January 2022 https www houstonchronicle com news houston weather article record breaking wind speed houston storm 18165106 php https www khou com article weather photos video storm damage houston 285 28680db6 a9ee 40cc b1e2 8ab360bde815 https www yourconroenews com neighborhood moco news article montgomery county homes damaged storm disaster 18170919 php https www khou com article weather storm damage hooks airport houston 285 24686c45 efd7 4602 96fc 6689e905b933 https www chron com weather article texas storm houston plane flipped 18165163 php NTP extends May 21st Ottawa area EF2 downburst www uwo ca Northern Tornadoes Project 9 June 2022 Retrieved 16 June 2022 Ottawa storm winds reached 190 km h researchers Ottawa 25 May 2022 Retrieved 16 June 2022 Derecho Storm Ranks 6th Largest Insured Loss Event in Canadian History ca finance yahoo com Retrieved 16 June 2022 Kumar Pokharel Ashok 2021 A straight line wind hit some parts of Bara and Parsa districts of Nepal Weather doi 10 1002 wea 4050 Roberts Samantha 10 August 2016 What happened in Cleveland Heights Tuesday night KLTV Retrieved 15 August 2016 a b Steer Jen Wright Matt 10 August 2016 Damage in Cleveland Heights caused by microburst Fox8 com Retrieved 15 August 2016 a b Reardon Kelly 10 August 2016 Wind gusts reached 58 mph lightning struck 10 times a minute in Tuesday s storms The Plain Dealer Retrieved 15 August 2016 a b Higgs Robert 11 August 2016 About 4 000 customers mostly in Cleveland Heights still without power from Tuesday s storms The Plain Dealer Retrieved 15 August 2016 Gorman Tom 8 September 2011 8 injured at Nellis AFB when aircraft shelters collapse in windstorm Thursday Sept 8 2011 9 p m Las Vegas Sun Retrieved 30 November 2011 Microbursts reported in Hegewisch Wheeling Chicago Breaking News 22 September 2010 Retrieved 30 November 2011 New York News Local Video Traffic Weather NY City Schools and Photos Homepage NY Daily News Daily News New York Power Restored to Tornado Slammed Residents Officials NBC New York 20 September 2010 Retrieved 30 November 2011 Charlottesville Continues Storm Cleanup Hundreds Remain Without Power Archived from the original on 3 September 2012 Retrieved 26 June 2010 and http www nbc29 com Global story asp S 12705577 Archived 6 August 2016 at the Wayback Machine Brian Kushida 11 June 2010 Strong Winds Rip Through SF Neighborhood News for Sioux Falls South Dakota Minnesota and Iowa Keloland com Archived from the original on 27 September 2011 Retrieved 30 November 2011 Gasper Christopher L 6 May 2009 Their view on matter Patriots checking practice facility The Boston Globe Retrieved 12 May 2009 One year after microburst recovery progresses KU edu Retrieved 21 July 2009 Storm Wrecks New Copters The New York Times 20 May 1989 Retrieved 2 June 2020 Heller Jean 7 May 2000 The Day Skyway Fell May 9 1980 St Petersburg Times Archived from the original on 23 March 2018 Retrieved 4 July 2007 Bibliography editFujita T T 1981 Tornadoes and Downbursts in the Context of Generalized Planetary Scales Journal of the Atmospheric Sciences 38 8 Wilson James W and Roger M Wakimoto 2001 The Discovery of the Downburst TT Fujita s Contribution Bulletin of the American Meteorological Society 82 1 National Weather Service Downbursts National Weather Service Forecast Office Columbia SC 5 May 2010 4 December 2010 http www erh noaa gov cae svrwx downburst htm Fujita T T 1981 Tornadoes and Downbursts in the Context of Generalized Planetary Scales Journal of the Atmospheric Sciences 38 8 Fujita T T 1985 The Downburst microburst and macroburst SMRP Research Paper 210 122 pp Wilson James W and Roger M Wakimoto 2001 The Discovery of the Downburst TT Fujita s Contribution Bulletin of the American Meteorological Society 82 1 External links edit nbsp Wikimedia Commons has media related to Downburst University of Illinois WW2010 Project NWS JetStream Project Online Weather School Downburst event Denton County Texas Archived 13 June 2017 at the Wayback Machine Downburst event Northern Wisconsin 4 July 1977 Dry downburst event North Carolina statewide 7 March 2004 The Semi official Microburst Handbook Homepage NOAA Taming the Microburst Windshear NASA Microbursts University of Wyoming Forecasting Microbursts amp Downbursts Forecast Systems Laboratory Retrieved from https en wikipedia org w index php title Downburst amp oldid 1189955593, wikipedia, wiki, book, books, library,

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