Heat burst
Encyclopedia
In meteorology
, a heat burst is a rare atmospheric phenomenon characterised by gusty winds and a rapid increase in temperature
and decrease in dew point
(moisture). Heat bursts typically occur during night-time and are associated with decaying thunderstorms.
Although this phenomenon is not fully understood, it is theorized that the event is caused when rain evaporates (virga
) into a parcel of cold dry air high in the atmosphere making the air denser than its surroundings. The parcel descends rapidly, warming due to compression, overshoots its equilibrium level
and reaches the surface, similar to a downburst
.
Recorded temperatures during heat bursts have reached well above 90 °F (32 °C), sometimes rising by 20 °F (11 °C) or more within only a few minutes. More extreme events have also been documented, where temperatures have been reported to exceed 120 °F (49 °C), although such extreme events have never been officially verified. Heat bursts are also characterised by extremely dry air and are sometimes associated with very strong, even damaging, wind
s.
Meteorology
Meteorology is the interdisciplinary scientific study of the atmosphere. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw breakthroughs occur after observing networks developed across several countries...
, a heat burst is a rare atmospheric phenomenon characterised by gusty winds and a rapid increase in temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
and decrease in dew point
Dew point
The dew point is the temperature to which a given parcel of humid air must be cooled, at constant barometric pressure, for water vapor to condense into liquid water. The condensed water is called dew when it forms on a solid surface. The dew point is a saturation temperature.The dew point is...
(moisture). Heat bursts typically occur during night-time and are associated with decaying thunderstorms.
Although this phenomenon is not fully understood, it is theorized that the event is caused when rain evaporates (virga
Virga
In meteorology, virga is an observable streak or shaft of precipitation that falls from a cloud but evaporates before reaching the ground. At high altitudes the precipitation falls mainly as ice crystals before melting and finally evaporating; this is usually due to compressional heating, because...
) into a parcel of cold dry air high in the atmosphere making the air denser than its surroundings. The parcel descends rapidly, warming due to compression, overshoots its equilibrium level
Equilibrium level
In meteorology, the equilibrium level , or level of neutral buoyancy , or limit of convection , is the height at which a rising parcel of air is at a temperature of equal warmth to it....
and reaches the surface, similar to a downburst
Downburst
A downburst is created by an area of significantly rain-cooled air that, after reaching ground level, spreads out in all directions producing strong winds. Unlike winds in a tornado, winds in a downburst are directed outwards from the point where it hits land or water...
.
Recorded temperatures during heat bursts have reached well above 90 °F (32 °C), sometimes rising by 20 °F (11 °C) or more within only a few minutes. More extreme events have also been documented, where temperatures have been reported to exceed 120 °F (49 °C), although such extreme events have never been officially verified. Heat bursts are also characterised by extremely dry air and are sometimes associated with very strong, even damaging, wind
Wind
Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...
s.
Some documented cases
- Atlantic, IowaAtlantic, IowaAtlantic is a city in and the county seat of Cass County, Iowa, United States, located along the East Nishnabotna River. The population was 7,112 in the 2010 census, a decline from the 7,257 population in the 2000 census. -History:...
, August 23, 2011: The observation at the Atlantic AWOS at 7:25pm local time had a temperature of 102 °F (38.9 °C) and a dewpoint of 7 °F (-13.9 °C). Three observations prior to this (6:55 pm), the temperature was 88 °F (31.1 °C) degrees and the dewpoint was 64 °F (17.8 °C). The 7 °F (-13.9 °C) dewpoint is considered likely to be incorrect, however, as AWOS stations have been known to have issues with dewpoints in low humidity environments. Scattered wind damage was also reported in association with the heat bursts, with one wind observation as high as 60 mile per hour. - Indianapolis, IndianaIndianapolis, IndianaIndianapolis is the capital of the U.S. state of Indiana, and the county seat of Marion County, Indiana. As of the 2010 United States Census, the city's population is 839,489. It is by far Indiana's largest city and, as of the 2010 U.S...
, July 3, 2011: Observations around 1:30 AM EDT in the area indicated the temperature rose and the dewpoint dropped nearly 15 degrees in a less than an hour, causing the relative humidity to drop nearly 40-50%. Winds increased rapidly, with gusts to near 50 mph. One NWS Indianapolis employee reported that his neighbor's patio furniture ended up in his backyard. The observation site at Eagle Creek Airpark (KEYE) best observed the temperature, dewpoint, and pressure changes. The site at Indianapolis International Airport (KIND) observed the strongest wind gusts associated with the heat burst. - Wichita, KansasWichita, KansasWichita is the largest city in the U.S. state of Kansas.As of the 2010 census, the city population was 382,368. Located in south-central Kansas on the Arkansas River, Wichita is the county seat of Sedgwick County and the principal city of the Wichita metropolitan area...
, June 9, 2011: Temperatures rose from 85 °F (29 °C) to 102 °F (39 °C) between 12:22 AM and 12:42 AM. The heat burst caused some wind damage (40-50 mph) and local residents reported the phenomenon to area weather stations. - Buenos Aires, Argentina, October 29, 2009: After a day with extremely high and unusual temperatures that peaked over 93.9 °F (34.4 °C) (air temperature 101.6 °F (38.7 °C)), at late midnight temperatures rose from 87.8 °F (31 °C) to 94.2 °F (34.6 °C) in a matter of minutes with wind gusts over 37 miles per hour (60 km/h)
- Delmarva PeninsulaDelmarva PeninsulaThe Delmarva Peninsula is a large peninsula on the East Coast of the United States, occupied by most of Delaware and portions of Maryland and Virginia...
, April 26, 2009: Temperatures rose from 68 °F (20 °C) to 87 °F (31 °C) between 10:00 PM and 2:00 AM following a series of heat bursts across the Eastern Shore. Double-digit temperature increases were reported from 1:00 AM to 2:00 AM at Salisbury, MarylandSalisbury, Maryland-Demographics:Salisbury is the principal city of the Salisbury-Ocean Pines CSA, a Combined Statistical Area that includes the Salisbury metropolitan area and the Ocean Pines micropolitan area , which had a combined population of 176,657 at the 2010 census.As of the census of 2000, there were...
(+13), Ocean City, MarylandOcean City, MarylandOcean City, sometimes known as OC, or OCMD, is an Atlantic Ocean resort town in Worcester County, Maryland, United States. Ocean City is widely known in the Mid-Atlantic region of the United States and is a frequent destination for vacationers in that area...
(+11), and Wallops Island, Virginia (+10). - Sioux Falls, South DakotaSioux Falls, South DakotaSioux Falls is the largest city in the U.S. state of South Dakota. Sioux Falls is the county seat of Minnehaha County, and also extends into Lincoln County to the south...
, August 3, 2008: Temperatures rose rapidly from the lower 70 °F (21 °C) to 101 °F (38 °C) in a matter of minutes. Wind speeds also rose with gusts up to 50–60 mph (80.5–96.6 km/h). - Cozad, NebraskaCozad, NebraskaCozad is a city in Dawson County, Nebraska, United States. The population was 3,977 at the 2010 census. The town is on the Great Plains of central Nebraska, along the Union Pacific Railroad and U.S. Highway 30, just north of the Platte River...
, June 26, 2008: Wind gusts reached 75 miles per hour (121 km/h), as the temperature rose 20 °F (11 °C) in a matter of minutes. - Midland, TexasMidland, TexasMidland is a city in and the county seat of Midland County, Texas, United States, on the Southern Plains of the state's western area. A small portion of the city extends into Martin County. As of 2010, the population of Midland was 111,147. It is the principal city of the Midland, Texas...
, June 16, 2008: At 11:25 pm a wind gust of 62 mph (100 km/h) occurred, and the temperature rose from 71 °F (21.7 °C) to 97 °F (36.1 °C) in minutes. (These measurements were taken from miles away, and theories point to 80–100 mph (128.7–160.9 km/h) winds in a 2–3 block perimeter.) - Emporia, KansasEmporia, KansasEmporia is a city in and the county seat of Lyon County, Kansas, United States. As of the 2010 census, the city population was 24,916. Emporia lies between Topeka and Wichita at the intersection of U.S. Route 50 with Interstates 335 and 35 on the Kansas Turnpike...
, 25 May 2008: Reported temperature jumped from 71 °F (21.7 °C) to 91 °F (32.8 °C) between 4:44 am and 5:11 am (CDT) as the result of wind activity from a slow moving thunderstorm some 40 miles (64 km) to the southwest. - Canby, MinnesotaCanby, MinnesotaAs of the census of 2000, there are 1,903 people, 842 households, and 453 families residing in the city. The population density is 876.5 people per square mile . There are 918 housing units at an average density of 422.8 per square mile...
, 16 July 2006: A heat burst formed in Western MinnesotaMinnesotaMinnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...
, pushing CanbyCanby, MinnesotaAs of the census of 2000, there are 1,903 people, 842 households, and 453 families residing in the city. The population density is 876.5 people per square mile . There are 918 housing units at an average density of 422.8 per square mile...
's temperature to 100 °F (37.8 °C), and causing a wind gust of 63 mph (52 kn; 101 km/h). The dew pointDew pointThe dew point is the temperature to which a given parcel of humid air must be cooled, at constant barometric pressure, for water vapor to condense into liquid water. The condensed water is called dew when it forms on a solid surface. The dew point is a saturation temperature.The dew point is...
fell from 70 °F (21.1 °C) to 32 °F (0 °C) over the course of one hour. - Hastings, NebraskaHastings, NebraskaHastings is a city in and the county seat of Adams County, Nebraska, United States. It is the principal city of the Hastings, Nebraska Micropolitan Statistical Area, which consists of Adams and Clay counties. The population was 24,907 at the 2010 census...
, 20 June 2006: During the early morning the surface temperature abruptly increased from approximately 75 °F (23.9 °C) to 94 °F (34.4 °C). - Sheppard Air Force BaseSheppard Air Force BaseSheppard Air Force Base is a United States Air Force base located five miles north of the central business district of Wichita Falls, in Wichita County, Texas, United States. It is the largest training base and most diversified in Air Education and Training Command...
Wichita Falls, TexasWichita Falls, TexasWichita Falls is a city in and the county seat of Wichita County, Texas, United States, United States. Wichita Falls is the principal city of the Wichita Falls Metropolitan Statistical Area, which encompasses all of Archer, Clay and Wichita counties. According to the U.S. Census estimate of 2010,...
, 12 June 2004: During late evening the surface temperature abruptly increased from approximately 83 °F (28.3 °C) to 94 °F (34.4 °C) and causing a wind gust of 72 mph (59 kn; 116 km/h). The dew pointDew pointThe dew point is the temperature to which a given parcel of humid air must be cooled, at constant barometric pressure, for water vapor to condense into liquid water. The condensed water is called dew when it forms on a solid surface. The dew point is a saturation temperature.The dew point is...
fell from 70 °F (21.1 °C) to 39 °F (3.9 °C) - MinnesotaMinnesotaMinnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...
and South DakotaSouth DakotaSouth Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...
, March 26, 1998: A temperature increase of 10–20 °F (6-11 °C) was reported in the towns of Marshall, MinnesotaMarshall, MinnesotaAs of the census of 2000, there were 12,735 people, 4,914 households, and 2,914 families residing in the city. The population density was 1,537.0 people per square mile . There were 5,182 housing units at an average density of 625.4 per square mile...
, Sioux Falls, South DakotaSioux Falls, South DakotaSioux Falls is the largest city in the U.S. state of South Dakota. Sioux Falls is the county seat of Minnehaha County, and also extends into Lincoln County to the south...
, Brookings, South DakotaBrookings, South DakotaBrookings is a city in Brookings County, South Dakota, United States. Brookings is the fourth largest city in South Dakota, with a population of 22,056 at the 2010 census. It is the county seat of Brookings County, and home to South Dakota State University, the largest institution of higher...
, and Montrose, South DakotaMontrose, South DakotaMontrose is a city in McCook County, South Dakota, United States. The population was 472 at the 2010 census.-Geography:Montrose is located at ....
during a two-hour period. - OklahomaOklahomaOklahoma is a state located in the South Central region of the United States of America. With an estimated 3,751,351 residents as of the 2010 census and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...
, May 22–May 23, 1996: The temperature in the towns of ChickashaChickasha, OklahomaChickasha is a city in and the county seat, business and employment center of Grady County, Oklahoma, United States. The population was 15,850 at the 2000 census. Chickasha is home to the University of Science and Arts of Oklahoma and hosts an annual Festival of Light celebration located at...
rose from 87.6 °F (30.9 °C) to 101.9 °F (38.8 °C) in just 25 minutes, while the temperature at NinnekahNinnekah, OklahomaNinnekah is a town in Grady County, Oklahoma, United States. The population was 994 at the 2000 census.-Geography:Ninnekah is located at .According to the United States Census Bureau, the town has a total area of , all of it land....
rose from 87.9 °F (31.1 °C) to 101.4 °F (39 °C) in 40 minutes. In addition, wind damage was reported as winds gusted to 95 mph (153 km/h) in LawtonLawton, OklahomaThe city of Lawton is the county seat of Comanche County, in the U.S. state of Oklahoma. Located in the southwestern region of Oklahoma approximately southwest of Oklahoma City, it is the principal city of the Lawton Oklahoma Metropolitan Statistical Area...
, 67 mph (108 km/h) in Ninnekah, and 63 mph (101 km/h) in Chickasha. - Kopperl, TexasKopperl, TexasKopperl is an unincorporated community in Bosque County, Texas, United States. It lies on the northwestern end of Lake Whitney, and has an estimated population of 225.-History:...
, 1960: A heat burst sent the air temperature to near 140 °F (60 °C), supposedly causing cotton crops to become desiccated and drying out vegetation. - PortugalPortugalPortugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...
, July 6, 1949: A heat burst reportedly drove the air temperature from 38 °C (100.4 °F) to 70 °C (158 °F) two minutes later (note that the highest temperature formally recognized on the Earth is 57.8 °C (136 °F) in LibyaLibyaLibya is an African country in the Maghreb region of North Africa bordered by the Mediterranean Sea to the north, Egypt to the east, Sudan to the southeast, Chad and Niger to the south, and Algeria and Tunisia to the west....
in 1922, and the former record has not been verified). - Cherokee, OklahomaCherokee, OklahomaCherokee is a city in Alfalfa County, Oklahoma, United States. The population was 1,630 at the 2000 census. It is the county seat of Alfalfa County.-History:Cherokee is the location of the Cherokee IOOF Lodge No...
, 11 July 1909: at 3:00 in the morning, a heat burst south of Cherokee, OklahomaCherokee, OklahomaCherokee is a city in Alfalfa County, Oklahoma, United States. The population was 1,630 at the 2000 census. It is the county seat of Alfalfa County.-History:Cherokee is the location of the Cherokee IOOF Lodge No...
reportedly caused the temperature to rise briefly to 136 °F (57.8 °C), desiccating crops in the area.