Heat wave

A heat wave, or heatwave,[1] is a period of excessively hot weather, which may be accompanied by high humidity, especially in oceanic climate countries. While definitions vary,[2] a heat wave is usually measured relative to the usual weather in the area and relative to normal temperatures for the season. Temperatures that people from a hotter climate consider normal can be called a heat wave in a cooler area if they are outside the normal climate pattern for that area.[3]

The term is applied both to hot weather variations and to extraordinary spells of hot which may occur only once a century. Severe heat waves have caused catastrophic crop failures, thousands of deaths from hyperthermia, and widespread power outages due to increased use of air conditioning. A heat wave is considered extreme weather that can be a natural disaster, and a danger because heat and sunlight may overheat the human body. Heat waves can usually be detected using forecasting instruments so that a warning call can be issued.


A definition based on Frich et al.'s Heat Wave Duration Index is that a heat wave occurs when the daily maximum temperature of more than five consecutive days exceeds the average maximum temperature by 5 °C (9 °F), the normal period being 1961–1990.[4]

A formal, peer-reviewed definition from the Glossary of Meteorology is:[5]

A period of abnormally and uncomfortably hot and usually humid weather.
To be a heat wave such a period should last at least one day, but conventionally it lasts from several days to several weeks. In 1900, A. T. Burrows more rigidly defined a “hot wave” as a spell of three or more days on each of which the maximum shade temperature reaches or exceeds 90 °F (32.2 °C). More realistically, the comfort criteria for any one region are dependent upon the normal conditions of that area.

The World Meteorological Organization, defines a heat wave as 5 or more consecutive days of prolonged heat in which the daily maximum temperature is higher than the average maximum temperature by 5 °C (9 °F) or more. [6] However, some nations have come up with their own criteria to define a heat wave.

Temperature anomalies 2007
Temperature anomalies, March to May 2007

In the Netherlands, a heat wave is defined as a period of at least 5 consecutive days in which the maximum temperature in De Bilt exceeds 25 °C (77 °F), provided that on at least 3 days in this period the maximum temperature in De Bilt exceeds 30 °C (86 °F). This definition of a heat wave is also used in Belgium and Luxembourg.

In Denmark, a national heat wave (hedebølge) is defined as a period of at least 3 consecutive days of which period the average maximum temperature across more than fifty percent of the country exceeds 28 °C (82.4 °F) – the Danish Meteorological Institute further defines a "warmth wave" (varmebølge) when the same criteria are met for a 25 °C (77.0 °F) temperature,[7] while in Sweden, a heat wave is defined as at least 5 days in a row with a daily high exceeding 25 °C (77.0 °F).[8]

In the United States, definitions also vary by region; however, a heat wave is usually defined as a period of at least two or more days of excessively hot weather.[9] In the Northeast, a heat wave is typically defined as three consecutive days where the temperature reaches or exceeds 90 °F (32.2 °C), but not always as this ties in with humidity levels to determine a heat index threshold.[10] The same does not apply to drier climates. A heat storm is a Californian term for an extended heat wave. Heat storms occur when the temperature reaches 100 °F (37.8 °C) for three or more consecutive days over a wide area (tens of thousands of square miles). The National Weather Service issues heat advisories and excessive heat warnings when unusual periods of hot weather are expected.

In Adelaide, South Australia, a heat wave is defined as five consecutive days at or above 35 °C (95 °F), or three consecutive days at or over 40 °C (104 °F).[11] The Australian Bureau of Meteorology defines a heat wave as "three days or more of maximum and minimum temperatures that are unusual for the location".[12] Until the introduction of this new Pilot Heatwave Forecast there was no national definition that described heatwave or measures of heatwave severity.[12]

In the United Kingdom, the Met Office operates a Heat Health Watch system which places each Local Authority region into one of four levels. Heatwave conditions are defined by the maximum daytime temperature and minimum nighttime temperature rising above the threshold for a particular region. The length of time spent above that threshold determines the particular level. Level 1 is normal summer conditions. Level 2 is reached when there is a 60% or higher risk that the temperature will be above the threshold levels for two days and the intervening night. Level 3 is triggered when the temperature has been above the threshold for the preceding day and night, and there is a 90% or higher chance that it will stay above the threshold in the following day. Level 4 is triggered if conditions are more severe than those of the preceding three levels. Each of the first three levels is associated with a particular state of readiness and response by the social and health services, and Level 4 is associated with more widespread response.[13]

A more general indicator that allows comparing heat waves in different regions of the World, characterized by different climates, has been recently developed.[14] This was used to estimate heat waves occurrence at the global scale from 1901 to 2010, finding a substantial and sharp increase in the amount of affected areas in the last two decades.[15]

Heat Waves from 1901 to 2010


Heat Wave
High pressure in the upper atmosphere traps heat near the ground, forming a heat wave

Heat waves form when high pressure aloft (from 10,000–25,000 feet (3,000–7,600 metres)) strengthens and remains over a region for several days up to several weeks.[16] This is common in summer (in both Northern and Southern Hemispheres) as the jet stream 'follows the sun'. On the equator side of the jet stream, in the upper layers of the atmosphere, is the high pressure area.

Summertime weather patterns are generally slower to change than in winter. As a result, this upper level high pressure also moves slowly. Under high pressure, the air subsides (sinks) toward the surface, warming and drying adiabatically. This warmer sinking air creates a high level inversion that acts as a dome capping the atmosphere, inhibiting convection, thereby trapping high humidity warm air below it. Typically, convection is present along the periphery of the cap where the pressure becomes less. This peripheral convection, however, can add to the high pressure dome by ventilating the upper level outflow of the thunderstorms into it. The end result is a continual build-up of heat at the surface that people experience as a heat wave.[17]

In the Eastern United States a heat wave can occur when a high pressure system originating in the Gulf of Mexico becomes stationary just off the Atlantic Seaboard (typically known as a Bermuda High). Hot humid air masses form over the Gulf of Mexico and the Caribbean Sea while hot dry air masses form over the desert Southwest and northern Mexico. The SW winds on the back side of the High continue to pump hot, humid Gulf air northeastward resulting in a spell of hot and humid weather for much of the Eastern States.[18]

In the Western Cape Province of South Africa, a heat wave can occur when a low pressure offshore and high pressure inland air combine to form a Bergwind. The air warms as it descends from the Karoo interior, and the temperature will rise about 10 °C from the interior to the coast. Humidities are usually very low, and the temperatures can be over 40 °C in summer. The highest official temperatures recorded in South Africa (51.5 °C) was recorded one summer during a bergwind occurring along the Eastern Cape coastline.[19][20]

Global warming boosts the probability of extreme weather events, like heat waves, far more than it boosts more moderate events.[21][22][23]

Health effects

NOAA national weather service: heat index
80 °F (27 °C) 82 °F (28 °C) 84 °F (29 °C) 86 °F (30 °C) 88 °F (31 °C) 90 °F (32 °C) 92 °F (33 °C) 94 °F (34 °C) 96 °F (36 °C) 98 °F (37 °C) 100 °F (38 °C) 102 °F (39 °C) 104 °F (40 °C) 106 °F (41 °C) 108 °F (42 °C) 110 °F (43 °C)
40% 80 °F (27 °C) 81 °F (27 °C) 83 °F (28 °C) 85 °F (29 °C) 88 °F (31 °C) 91 °F (33 °C) 94 °F (34 °C) 97 °F (36 °C) 101 °F (38 °C) 105 °F (41 °C) 109 °F (43 °C) 114 °F (46 °C) 119 °F (48 °C) 124 °F (51 °C) 130 °F (54 °C) 136 °F (58 °C)
45% 80 °F (27 °C) 82 °F (28 °C) 84 °F (29 °C) 87 °F (31 °C) 89 °F (32 °C) 93 °F (34 °C) 96 °F (36 °C) 100 °F (38 °C) 104 °F (40 °C) 109 °F (43 °C) 114 °F (46 °C) 119 °F (48 °C) 124 °F (51 °C) 130 °F (54 °C) 137 °F (58 °C)
50% 81 °F (27 °C) 83 °F (28 °C) 85 °F (29 °C) 88 °F (31 °C) 91 °F (33 °C) 95 °F (35 °C) 99 °F (37 °C) 103 °F (39 °C) 108 °F (42 °C) 113 °F (45 °C) 118 °F (48 °C) 124 °F (51 °C) 131 °F (55 °C) 137 °F (58 °C)
55% 81 °F (27 °C) 84 °F (29 °C) 86 °F (30 °C) 89 °F (32 °C) 93 °F (34 °C) 97 °F (36 °C) 101 °F (38 °C) 106 °F (41 °C) 112 °F (44 °C) 117 °F (47 °C) 124 °F (51 °C) 130 °F (54 °C) 137 °F (58 °C)
60% 82 °F (28 °C) 84 °F (29 °C) 88 °F (31 °C) 91 °F (33 °C) 95 °F (35 °C) 100 °F (38 °C) 105 °F (41 °C) 110 °F (43 °C) 116 °F (47 °C) 123 °F (51 °C) 129 °F (54 °C) 137 °F (58 °C)
65% 82 °F (28 °C) 85 °F (29 °C) 89 °F (32 °C) 93 °F (34 °C) 98 °F (37 °C) 103 °F (39 °C) 108 °F (42 °C) 114 °F (46 °C) 121 °F (49 °C) 128 °F (53 °C) 136 °F (58 °C)
70% 83 °F (28 °C) 86 °F (30 °C) 90 °F (32 °C) 95 °F (35 °C) 100 °F (38 °C) 105 °F (41 °C) 112 °F (44 °C) 119 °F (48 °C) 126 °F (52 °C) 134 °F (57 °C)
75% 84 °F (29 °C) 88 °F (31 °C) 92 °F (33 °C) 97 °F (36 °C) 103 °F (39 °C) 109 °F (43 °C) 116 °F (47 °C) 124 °F (51 °C) 132 °F (56 °C)
80% 84 °F (29 °C) 89 °F (32 °C) 94 °F (34 °C) 100 °F (38 °C) 106 °F (41 °C) 113 °F (45 °C) 121 °F (49 °C) 129 °F (54 °C)
85% 85 °F (29 °C) 90 °F (32 °C) 96 °F (36 °C) 102 °F (39 °C) 110 °F (43 °C) 117 °F (47 °C) 126 °F (52 °C) 135 °F (57 °C)
90% 86 °F (30 °C) 91 °F (33 °C) 98 °F (37 °C) 105 °F (41 °C) 113 °F (45 °C) 122 °F (50 °C) 131 °F (55 °C)
95% 86 °F (30 °C) 93 °F (34 °C) 100 °F (38 °C) 108 °F (42 °C) 117 °F (47 °C) 127 °F (53 °C)
100% 87 °F (31 °C) 95 °F (35 °C) 103 °F (39 °C) 112 °F (44 °C) 121 °F (49 °C) 132 °F (56 °C)

The heat index (as shown in the table above) is a measure of how hot it feels when relative humidity is factored with the actual air temperature. Hyperthermia, also known as heat stroke, becomes commonplace during periods of sustained high temperature and humidity. Older adults, very young children, and those who are sick or overweight are at a higher risk for heat-related illness. The chronically ill and elderly are often taking prescription medications (e.g., diuretics, anticholinergics, antipsychotics, and antihypertensives) that interfere with the body's ability to dissipate heat.[24]

Heat edema presents as a transient swelling of the hands, feet, and ankles and is generally secondary to increased aldosterone secretion, which enhances water retention. When combined with peripheral vasodilation and venous stasis, the excess fluid accumulates in the dependent areas of the extremities. The heat edema usually resolves within several days after the patient becomes acclimated to the warmer environment. No treatment is required, although wearing support stockings and elevating the affected legs will help minimize the edema.

Heat rash, also known as prickly heat, is a maculopapular rash accompanied by acute inflammation and blocked sweat ducts. The sweat ducts may become dilated and may eventually rupture, producing small pruritic vesicles on an erythematous base. Heat rash affects areas of the body covered by tight clothing. If this continues for a duration of time it can lead to the development of chronic dermatitis or a secondary bacterial infection. Prevention is the best therapy. It is also advised to wear loose-fitting clothing in the heat. However, once heat rash has developed, the initial treatment involves the application of chlorhexidine lotion to remove any desquamated skin. The associated itching may be treated with topical or systemic antihistamines. If infection occurs a regimen of antibiotics is required.

Summer 1936 US Temperature
The 1936 North American heat wave. Record temperatures were based on 112 year records

Heat cramps are painful, often severe, involuntary spasms of the large muscle groups used in strenuous exercise. Heat cramps tend to occur after intense exertion. They usually develop in people performing heavy exercise while sweating profusely and replenishing fluid loss with non-electrolyte containing water. This is believed to lead to hyponatremia that induces cramping in stressed muscles. Rehydration with salt-containing fluids provides rapid relief. Patients with mild cramps can be given oral .2% salt solutions, while those with severe cramps require IV isotonic fluids. The many sport drinks on the market are a good source of electrolytes and are readily accessible.

Heat syncope is related to heat exposure that produces orthostatic hypotension. This hypotension can precipitate a near-syncopal episode. Heat syncope is believed to result from intense sweating, which leads to dehydration, followed by peripheral vasodilation and reduced venous blood return in the face of decreased vasomotor control. Management of heat syncope consists of cooling and rehydration of the patient using oral rehydration therapy (sport drinks) or isotonic IV fluids. People who experience heat syncope should avoid standing in the heat for long periods of time. They should move to a cooler environment and lie down if they recognize the initial symptoms. Wearing support stockings and engaging in deep knee-bending movements can help promote venous blood return.

Heat exhaustion is considered by experts to be the forerunner of heat stroke (hyperthermia). It may even resemble heat stroke, with the difference being that the neurologic function remains intact. Heat exhaustion is marked by excessive dehydration and electrolyte depletion. Symptoms may include diarrhea, headache, nausea and vomiting, dizziness, tachycardia, malaise, and myalgia. Definitive therapy includes removing patients from the heat and replenishing their fluids. Most patients will require fluid replacement with IV isotonic fluids at first. The salt content is adjusted as necessary once the electrolyte levels are known. After discharge from the hospital, patients are instructed to rest, drink plenty of fluids for 2–3 hours, and avoid the heat for several days. If this advice is not followed it may then lead to heat stroke.

One public health measure taken during heat waves is the setting-up of air-conditioned public cooling centers.


Heat waves are the most lethal type of weather phenomenon in the United States. Between 1992 and 2001, deaths from excessive heat in the United States numbered 2,190, compared with 880 deaths from floods and 150 from hurricanes.[25] The average annual number of fatalities directly attributed to heat in the United States is about 400.[26] The 1995 Chicago heat wave, one of the worst in US history, led to approximately 739 heat-related deaths over a period of 5 days.[27] Eric Klinenberg has noted that in the United States, the loss of human life in hot spells in summer exceeds that caused by all other weather events combined, including lightning, rain, floods, hurricanes, and tornadoes.[28][29] Despite the dangers, Scott Sheridan, professor of geography at Kent State University, found that less than half of people 65 and older abide by heat-emergency recommendations like drinking lots of water. In his study of heat-wave behavior, focusing particularly on seniors in Philadelphia, Phoenix, Toronto, and Dayton, Ohio, he found that people over 65 "don't consider themselves seniors." One of his older respondents said: "Heat doesn't bother me much, but I worry about my neighbors."[30]

According to the Agency for Health care Research and Quality, about 6,200 Americans are hospitalized each summer due to excessive heat, and those at highest risk are poor, uninsured or elderly.[31] More than 70,000 Europeans died as a result of the 2003 European heat wave.[32] Also more than 2,000 people died in Karachi, Pakistan in June 2015 due to a severe heat wave with temperatures as high as 49 °C (120 °F).[33][34]

Our concern now is focusing on predicting the future likelihood of heat waves and their severity. In addition, because in most of the world most of those suffering the impacts of a heat wave will be inside a building, and this will modify the temperatures they are exposed to, there is the need to link climate models to building models. This means producing example time series of future weather.[35][36] Other work has shown that future mortality due to heat waves could be reduced if buildings were better designed to modify the internal climate, or if the occupants were better educated about the issues, so they can take action in time.[37][38]

Underreporting and "Harvesting" effect

The number of heat fatalities is likely highly underreported due to a lack of reports and misreports.[26] Part of the mortality observed during a heat wave, however, can be attributed to a so-called "harvesting effect", a term for a short-term forward mortality displacement. It has been observed that for some heat waves, there is a compensatory decrease in overall mortality during the subsequent weeks after a heat wave. Such compensatory reductions in mortality suggest that heat affects especially those so ill that they "would have died in the short term anyway".[39]

Another explanation for underreporting is the social attenuation in most contexts of heat waves as a health risk. As shown by the deadly French heat wave in 2003, heat wave dangers result from the intricate association of natural and social factors.[40]

Psychological and sociological effects

In addition to physical stress, excessive heat causes psychological stress, to a degree which affects performance, and is also associated with an increase in violent crime.[41] High temperatures are associated with increased conflict both at the interpersonal level and at the societal level. In every society, crime rates go up when temperatures go up, particularly violent crimes such as assault, murder, and rape. Furthermore, in politically unstable countries, high temperatures are an aggravating factor that lead toward civil wars.[42]

Additionally, high temperatures have a significant effect on income. A study of counties in the United States found that economic productivity of individual days declines by about 1.7% for each degree Celsius above 15 °C (59 °F).[43]

Power outages

Abnormally hot temperatures can cause electricity demand to increase during the peak summertime hours of 4 to 7 p.m. when air conditioners are straining to overcome the heat. If a hot spell extends to three days or more, however, nighttime temperatures do not cool down, and the thermal mass in homes and buildings retains the heat from previous days. This heat build-up causes air conditioners to turn on earlier and to stay on later in the day. As a result, available electricity supplies are challenged during a higher, wider, peak electricity consumption period.

Heat waves often lead to electricity spikes due to increased air conditioning use, which can create power outages, exacerbating the problem. During the 2006 North American heat wave, thousands of homes and businesses went without power, especially in California. In Los Angeles, electrical transformers failed, leaving thousands without power for as long as five days.[44] The 2009 South Eastern Australia Heat Wave caused the city of Melbourne, Australia to experience some major power disruptions which left over half a million people without power as the heat wave blew transformers and overloaded a power grid.


If a heat wave occurs during a drought, which dries out vegetation, it can contribute to bushfires and wildfires. During the disastrous heat wave that struck Europe in 2003, fires raged through Portugal, destroying over 3,010 square kilometres (1,160 sq mi) or 301,000 hectares (740,000 acres) of forest and 440 square kilometres (170 sq mi) or 44,000 hectares (110,000 acres) of agricultural land and causing an estimated 1 billion worth of damage.[45] High end farmlands have irrigation systems to back up crops with. Heat waves cause wildfires.

Physical damage

Heat waves can and do cause roads and highways to buckle and melt,[46] water lines to burst, and power transformers to detonate, causing fires. See the 2006 North American heat wave article about heat waves causing physical damage.

Heat waves can also damage rail roads, such as buckling and kinking rails, which can lead to slower traffic, delays, and even cancellations of service when rails are too dangerous to traverse by trains. Sun kinking is caused when certain types of rail design like short section rails welded together or fish plate rails expand and push on other sections of rail causing them to warp and kink. Sun kinking can be a serious problem in hotter climates like Southern USA, parts of Canada, the Middle East, etc.

In the 2013 heatwave in England, gritters (normally only seen in snow) were sent out to grit melting tarmac roads.[47]

Future environmental effects

Climate models reveal that future heat waves will have a more intense geologic pattern.[48] The famous heat wave events of Chicago in 1995 and the European heat wave of 2003 regions will experience longer, more frequent and more intense heat waves in the latter 21st century.[48] Heat waves today in Europe and North America happen parallel to the conditions of atmospheric circulation.[48] Increased anthropogenic activities causing increased greenhouse gas emissions show that heat waves will be more severe.[48]

Heat waves and droughts as a result, minimize ecosystem carbon uptake. [49] Carbon uptake is also known as carbon sequestration. Extreme heat wave events are predicted to happen with increased global warming, which puts stress on ecosystems.[49] Stress on ecosystems due to future intensified heat waves will reduce biological productivity. [49] This will cause changes in the ecosystem's carbon cycle feedback because there will be less vegetation to hold the carbon from the atmosphere, which will only contribute more to atmospheric warming. [49]


June 2019 was the hottest month on record worldwide, the effects of this were especially prominent in Europe.[50] The effects of climate change have been projected to make heat waves in places such as Europe up to five times more likely to occur. Among other effects, increased wildfires in places such as Spain can also be attributed to heat waves.[51]

In July of 2019, over 50 million people in the United States were present in a jurisdiction with any type of heat advisory - heat is the deadliest type of extreme weather in the United States. Scientists predicted that in the days following the issuance of these warnings, many records for highest low temperatures will be broken. (I.e. - the lowest temperature in a 24-hour period will be higher than any low temperature measured before.)[52]

See also


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External links

1936 North American heat wave

The 1936 North American heat wave was one of the most severe heat waves in the modern history of North America. It took place in the middle of the Great Depression and Dust Bowl of the 1930s and caused catastrophic human suffering and an enormous economic toll. The death toll exceeded 5,000, and huge numbers of crops were destroyed by the heat and lack of moisture. Many state and city record high temperatures set during the 1936 heat wave stood until the summer 2012 North American heat wave. The 1936 heat wave followed one of the coldest winters on record.

1976 British Isles heat wave

The 1976 British Isles heat wave led to the second hottest summer average temperature in the UK since records began. At the same time, the country suffered a severe drought.

It was one of the driest, sunniest and warmest summers (June/July/August) in the 20th century, although the summer of 1995 is now regarded as the driest. Only a few places registered more than half their average summer rainfall. In the CET record, it was the warmest summer in that series.

It was the warmest summer in the Aberdeen area since at least 1864, and the driest summer since 1868 in Glasgow.

1990 United Kingdom heat wave

During the 1990 heat wave in the United Kingdom a weather station in Nailstone, Leicestershire, recorded a temperature of 37.1 °C (98.8 °F) for Cheltenham, Gloucestershire, the highest temperature ever known in Britain, one full Fahrenheit degree above the previous record, set in 1911.

1995 Chicago heat wave

The 1995 Chicago heat wave was a heat wave which led to 739 heat-related deaths in Chicago over a period of five days. Most of the victims of the heat wave were elderly poor residents of the city, who could not afford air conditioning and did not open windows or sleep outside for fear of crime. The heat wave also heavily impacted the wider Midwestern region, with additional deaths in both St. Louis, Missouri and Milwaukee, Wisconsin.

2003 European heat wave

The 2003 European heat wave led to the hottest summer on record in Europe since at least 1540. France was hit especially hard. The heat wave led to health crises in several countries and combined with drought to create a crop shortfall in parts of Southern Europe. Peer-reviewed analysis places the European death toll at more than 70,000.The predominant heat was recorded in July and August, partly a result of the western European seasonal lag from the maritime influence of the Atlantic warm waters in combination with hot continental air and strong southerly winds.

2006 European heat wave

The 2006 European heat wave was a period of exceptionally hot weather that arrived at the end of June 2006 in certain European countries. The United Kingdom, France, Belgium, the Netherlands, Luxembourg, Italy, Poland, the Czech Republic, Hungary, Germany and western parts of Russia were most affected. Several records were broken. In the Netherlands, Belgium, Germany, Ireland and the United Kingdom, July 2006 was the warmest month since official measurements began.

2009 southeastern Australia heat wave

The 2009 southeastern Australia heat wave was a heat wave that commenced in late January and led to record-breaking prolonged high temperatures in the region. The heat wave is considered one of the, if not the, most extreme in the region's history. During the heat wave, fifty separate locations set various records for consecutive, highest daytime and overnight temperatures. The highest temperature recorded during the heat wave was 48.8 °C (119.8 °F) in Hopetoun, Victoria, a record for the state. Many locations through the region recorded all-time high temperatures including capital cities Adelaide, which reached its third-highest temperature, 45.7 °C (114.3 °F), and Melbourne, which recorded its highest-ever temperature on record, 46.4 °C (115.5 °F). Both cities broke records for the most consecutive days over 40 °C (104 °F), while Mildura, Victoria recorded an all-time record twelve consecutive days over 43 °C (109 °F).

The exceptional heat wave was caused by a slow-moving high-pressure system that settled over the Tasman Sea, with a combination of an intense tropical low located off the North West Australian coast and a monsoon trough over Northern Australia, which produced ideal conditions for hot tropical air to be directed down over southeastern Australia. The heat began in South Australia on 25 January but became more widespread over southeast Australia by 27 January. A weak cool change moved over the southern coastal areas bringing some relief on 30 January, including Melbourne, where the change arrived that evening, dropping temperatures to an average of 30.8 °C (87.4 °F). Higher temperatures returned on the following weekend with Melbourne recording its hottest day since records began in 1855, 46.4 °C (115.5 °F).The heat wave generated extreme fire conditions during the peak of the 2008–09 Australian bushfire season, causing many bushfires in the affected region, contributing to the extreme bushfire conditions on 7 February, also known as the Black Saturday bushfires, which claimed 173 lives in Victoria.

2010 Northern Hemisphere heat waves

The 2010 Northern Hemisphere summer heat waves included severe heat waves that impacted most of the United States, Kazakhstan, Mongolia, China, Hong Kong, North Africa and the European continent as a whole, along with parts of Canada, Russia, Indochina, South Korea and Japan during May, June, July, and August 2010. The first phase of the global heatwaves was caused by a moderate El Niño event, which lasted from June 2009 to May 2010. The first phase lasted only from April 2010 to June 2010, and caused only moderate above average temperatures in the areas affected. But it also set new record high temperatures for most of the area affected, in the Northern Hemisphere. The second phase (the main, and most devastating phase) was caused by a very strong La Niña event, which lasted from June 2010 to June 2011. According to meteorologists, the 2010–11 La Niña event was one of the strongest La Niña events ever observed. That same La Niña event also had devastating effects in the Eastern states of Australia. The second phase lasted from June 2010 to October 2010, caused severe heat waves, and multiple record-breaking temperatures. The heatwaves began on April 2010, when strong anticyclones began to develop, over most of the affected regions, in the Northern Hemisphere. The heatwaves ended in October 2010, when the powerful anticyclones over most of the affected areas dissipated.

The heat wave during the summer of 2010 was at its worst in June, over the Eastern United States, Middle East, Eastern Europe and European Russia, and over Northeastern China and southeastern Russia. June 2010 marked the fourth consecutive warmest month on record globally, at 0.66 °C (1.22 °F) above average, while the period April–June was the warmest ever recorded for land areas in the Northern Hemisphere, at 1.25 °C (2.25 °F) above average. The previous record for the global average temperature in June was set in 2005 at 0.66 °C (1.19 °F), and the previous warm record for April–June over Northern Hemisphere land areas was 1.16 °C (2.09 °F), set in 2007. The strongest of the anticyclones, the one situated over Siberia, registered a maximum high pressure of 1040 millibars. The weather caused forest fires in China, where three in a team of 300 died fighting a fire that broke out in the Binchuan County of Dali, as Yunnan suffered the worst drought in 60 years by February 17. A major drought was reported across the Sahel as early as January. In August, a section of the Petermann Glacier tongue connecting northern Greenland, the Nares Strait and the Arctic Ocean broke off, the biggest ice shelf in the Arctic to detach in 48 years. By the time the heatwaves had ended in late October 2010, about $500 billion (2011 USD) of damage was done, in the Northern Hemisphere alone.

The World Meteorological Organization stated that the heat waves, droughts and flooding events fit with predictions based on global warming for the 21st century, include those based on the Intergovernmental Panel on Climate Change's 2007 4th Assessment Report. Some climatologists argue that these weather events would not have happened if the atmospheric carbon dioxide was at pre-industrial levels.

2013 Great Britain and Ireland heat wave

The 2013 heat wave in the United Kingdom and Ireland was a period of unusually hot weather primarily in July 2013, with isolated warm days in June and August. A prolonged high pressure system over Britain and Ireland caused higher than average temperatures for 19 consecutive days in July, reaching 33.5 °C (92.3 °F) at Heathrow and Northolt. Following a brief period of cooler weather at the end of July, temperatures temporarily rose again, peaking at 34.1 °C (93.4 °F) on 1 August in the United Kingdom, the warmest the country had seen since July 2006, and 31 °C (88 °F) in Ireland. At 19 days, the July heatwave was the longest continuous period of hot weather in the UK since August 1997.

2018 British Isles heat wave

The 2018 Britain and Ireland heat wave was a period of unusually hot weather that took place in June, July and August. It led to record-breaking temperatures in the UK and Ireland. It caused widespread drought, hosepipe bans, crop failures, and a number of wildfires. These wildfires worst affected northern moorland areas around the Greater Manchester region, the largest was at Saddleworth Moor and another was at Winter Hill, together these burned over 14 square miles (36 km2) of land over a period of nearly a month.A heat wave was officially declared on 22 June, with Scotland and Northern Ireland recording temperatures above 30 °C (86 °F) for the first time since the July 2013 heat wave. The British Isles were in the middle of a strong warm anticyclone inside a strong northward meander of the jet stream, this was part of the wider 2018 European heat wave. The Met Office declared summer 2018 the joint hottest on record together with 2006, 2003 and 1976.

2019 heat wave in India and Pakistan

From mid-May to mid-June 2019, India and Pakistan had a severe heat wave. It was one of the hottest and longest heat waves since the two countries began recording weather reports. The highest temperatures occurred in Churu, Rajasthan, reaching up to 50.8 °C (123.4 °F), a near record high in India, missing the record of 51.0 °C (123.8 °F) set in 2016 by a fraction of a degree. As of 12 June 2019, 32 days are classified as parts of the heatwave, making it the second longest ever recorded.As a result of hot temperatures and inadequate preparation, more than 184 people died in the state of Bihar, with many more deaths reported in other parts of the country. In Pakistan, five infants died after extreme heat exposure.The heat wave coincided with extreme droughts and water shortages across India and Pakistan. In mid-June, reservoirs that previously supplied Chennai ran dry, depriving millions. The water crisis was exacerbated by high temperatures and lack of preparation, causing protests and fights that sometimes led to killing and stabbing.

Calypso Heat Wave

Calypso Heat Wave is a 1957 American film starring Merry Anders, Meg Myles and, as herself, Maya Angelou.It was an attempt by producer Sam Katzman to repeat the success of Rock Around the Clock with calypso music. It was originally known as Juke Box Jamboree.

ECW Heat Wave

Heat Wave was a professional wrestling event produced by Eastern/Extreme Championship Wrestling. It took place annually from 1994 to 2000. The 1998-2000 iterations of Heat Wave aired on pay-per-view (PPV), while the 1997 iteration was an Internet pay-per-view (iPPV). The footage from the seven Heat Wave events is owned by WWE.

Heat Wave (Irving Berlin song)

"Heat Wave" is a popular song written by Irving Berlin for the 1933 musical As Thousands Cheer, and introduced in the show by Ethel Waters.

Heat Wave (Martha and the Vandellas song)

"Heat Wave" is a 1963 song written by the Holland–Dozier–Holland songwriting team. It was first made popular by the Motown vocal group Martha and the Vandellas. Released as a 45 rpm single on July 9, 1963, on the Motown subsidiary Gordy label, it hit number 1 on the Billboard Hot R&B chart—where it stayed for four weeks running—and peaking at number 4 on the Billboard Hot 100.

It was recorded 12 years later by rock vocalist Linda Ronstadt on her Platinum-selling 1975 album Prisoner in Disguise. Ronstadt's version of the song was released as a single in September 1975, reaching number 5 in Billboard, 4 in Cash Box, and 6 in Record World. In 2010, British musician Phil Collins spent a single week (number 28) on the Billboard Adult Contemporary listing with his retooling of the song—a smooth combination of both versions.

Heat Wave (comics)

Heat Wave (Mick Rory) is an antihero and supervillain appearing in comic books published by DC Comics, commonly as an enemy of The Flash and a member of The Rogues along with Captain Cold.

Actor Dominic Purcell has portrayed the character in The CW's television series The Flash and currently is in Legends of Tomorrow.

July 2019 European heat wave

The July 2019 European heat wave was a period of exceptionally hot weather, setting all-time high temperature records in Belgium, Germany, Luxembourg, the Netherlands, and the United Kingdom. It followed the June 2019 European heat wave, which killed over 567 people, and exceeded previous records by 3 °C (5.4 °F) in Belgium, by 0.3 °C (0.54 °F) in Luxembourg, by 2.1 °C (3.8 °F) in Germany and the Netherlands and by 0.2 °C (0.36 °F) in the United Kingdom.

The deaths of 868 people in France and one person in Belgium were reported, along with thousands of animals when ventilation systems in barns were overwhelmed. Due to high river water temperatures and sluggish flows, particularly in France and to some extent Germany, a number of thermal power stations that use once-through cooling and do not have cooling towers had to reduce output or shut down to avoid breaching environmental limits on river water temperature designed to protect aquatic life.

List of heat waves

This is a partial list of temperature phenomena that have been labeled as heat waves, listed in order of occurrence.

List of natural disasters by death toll

A natural disaster is a sudden event that causes widespread destruction, major collateral damage or loss of life, brought about by forces other than the acts of human beings. A natural disaster might be caused by earthquakes, flooding, volcanic eruption, landslide, hurricanes etc. To be classified as a disaster, it will have profound environmental effect and/or human loss and frequently incurs financial loss.

Heat waves
North America


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