This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (September 2007)

This article needs attention from an expert on the subject. Please add a reason or a talk parameter to this template to explain the issue with the article. WikiProject Meteorology may be able to help recruit an expert. (November 2009)

The 2003 European heat wave was the hottest summer on record in Europe since at least 1540.^[1] 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 Southern Europe. More than 70,000 Europeans died as a result of the heat wave.^[2]

Difference in average temperature (2000, 2001, 2002 and 2004) from 2003, covering the date range of 20 July – 20 August^[3]

Country-by-country[link]

France[link]

In France, there were 14,802 heat-related deaths (mostly among the elderly) during the heat wave, according to the French National Institute of Health.^[4][5] France does not commonly have very hot summers, particularly in the northern areas,^[6] but seven days with temperatures of more than 40 °C (104 °F) were recorded in Auxerre, Yonne between July and August 2003. Because of the usually relatively mild summers, most people did not know how to react to very high temperatures (for instance, with respect to rehydration), and most single-family homes and residential facilities built in the last 50 years were not equipped with air conditioning. Furthermore, while there were contingency plans for a variety of natural and man-made catastrophes, high temperatures had never been considered a major hazard.

The catastrophe occurred in August, a month in which many people, including government ministers and physicians, are on holiday. Many bodies were not claimed for many weeks because relatives were on holiday. A refrigerated warehouse outside Paris was used by undertakers as they did not have enough space in their own facilities. On 3 September 2003, fifty-seven bodies still left unclaimed in the Paris area were buried.

The high number of deaths can be explained by the conjunction of seemingly unrelated events. Most nights in France are cool, even in summer. As a consequence, houses (usually of stone, concrete or brick construction) do not warm too much during the daytime and radiate minimal heat at night, and air conditioning is usually unnecessary. During the heat wave, temperatures remained at record highs even at night, preventing the usual cooling cycle. Elderly persons living by themselves had never faced such extreme hotness before and did not know how to react or were too mentally or physically impaired by the heat to make the necessary adaptations themselves. Elderly persons with family support or those residing in nursing homes were more likely to have others who could make the adjustments for them. This led to statistically improbable survival rates with the weakest group having fewer deaths than more physically fit persons; most of the heat victims came from the group of elderly persons not requiring constant medical care or living alone without immediate family.

That shortcomings of the nation's health system could allow such a death toll is a matter of controversy in France. The administration of President Jacques Chirac and Prime Minister Jean-Pierre Raffarin laid the blame on families who had left their elderly behind without caring for them, the 35-hour workweek, which affected the amount of time doctors could work and family practitioners vacationing in August. Many companies traditionally closed in August, so people had no choice about when to vacation. Family doctors were still in the habit of vacationing at the same time. It is not clear that more physicians would have helped as the main limitation was not the health system but locating old people needing assistance.

The opposition, as well as many of the editorials of the local press, have blamed the administration. Many blamed Health Minister Jean-François Mattei for failing to return from his vacation when the heat wave became serious, and his aides for blocking emergency measures in public hospitals (such as the recalling of physicians). A particularly vocal critic was Dr. Patrick Pelloux, head of the union of emergency physicians, who blamed the Raffarin administration for ignoring warnings from health and emergency professionals and trying to minimize the crisis. Mattei lost his ministerial post in a cabinet reshuffle on 31 March 2004.

Not everyone blamed the government. "The French family structure is more dislocated than elsewhere in Europe, and prevailing social attitudes hold that once older people are closed behind their apartment doors or in nursing homes, they are someone else's problem," said Stéphane Mantion, an official with the French Red Cross. "These thousands of elderly victims didn't die from a heat wave as such, but from the isolation and insufficient assistance they lived with day in and out, and which almost any crisis situation could render fatal."^[7]

Portugal[link]

There were extensive forest fires in Portugal. Five percent of the countryside and ten percent of the forests (215,000 hectares^[5]) were destroyed, an estimated 4,000 square kilometres (1,500 sq mi). Eighteen people died in the fires and there were an estimated 1866 to 2039 heat related deaths over all.^[8] Temperatures reached as high as 48 °C (118 °F) in Amareleja. The first of August was the hottest day in centuries, with night temperatures well above 30 °C (86 °F). A freak storm developed on the southern region during that dawn. A hot, strong saharan wind blew during the subsequent days of that week.^[9][10] 7

Netherlands[link]

There were about 1,500^[5][11] heat related deaths in the Netherlands, again largely the elderly. The heat wave here broke no records, although 4 tropical weather designated days in mid-July, preceding the official wave, are not counted due to a cool day in between and the nature of the Netherlands specification/definition of a heat wave.^[11] The highest temperature recorded this heatwave was on 7 August, when in Arcen, in Limburg, a temperature of 37.8 °C was reached, 0.8 °C below the national record (since 1704). It happened only twice that a higher temperature was recorded. On 8 August a temperature of 37.7 °C was recorded, and 12 August saw a temperature of 37.2 °C.^[12]

Spain[link]

There were 141 deaths in Spain^{[citation needed]}. Temperature records were broken in various cities including 45.1 °C (113.2 °F) in Jerez , 41 °C (106 °F), with the heat wave being more felt in typically cooler northern Spain. Thus, record temperatures were reached in Girona,^[13] 38.8 °C (101.8 °F) in Burgos,^[14] 38.6 °C (101.5 °F) in San Sebastián,^[14] 36 °C (97 °F) in Pontevedra^[15] and 36 °C (97 °F) in Barcelona.^[16] In Sevilla was 45.2 °C (113.4 °F) although the record was in 1995 with 46.6 °C (115.9 °F).^[17]

Italy[link]

The summer 2003 was among the warmest in the last three centuries,^[18] and the maximum temperatures of July and August remained above 30 °C.^[18] The high humidity emphasized the perception of heat and population suffering.^[18] Several reports about strong positive temperature anomalies exist, for instance from Toscana^[19] and Veneto.^[20] Temperatures rose far above their means in most of the Country and reached very high mean values especially in terms of heat persistence; for instance the weather station of Catenanuova, in Sicily, had a monthly mean of 31.5 °C (88.7 °F) in July 2003, with an absolute maximum of 46.0 °C (114.8 °F) on 17 July, with monthly mean maximum temperatures of 36.0 °C (96.8 °F), 38.9 °C (102.0 °F) and 38.0 °C (100.4 °F) in June, July and August 2003 respectively.^[21]

Germany[link]

In Germany, a record temperature of 40.4 °C (104.7 °F) was recorded at Roth bei Nürnberg, Bavaria.^{[citation needed]} But some experts suspect that the highest temperatures occurred in the upper Rhine plain, which is known for very high temperatures. At some stations (private stations, for example Mannheim or Frankenthal), temperatures over 41 °C (106 °F) were reported, but not recognized by official statistics. With only half the normal rainfall, rivers were at their lowest this century,^{[citation needed]} and shipping could not navigate the Elbe or Danube. Around 300 people^[5]—mostly elderly—died during the 2003 heatwave in Germany.

Switzerland[link]

Melting glaciers in the Alps caused avalanches and flash floods in Switzerland. A new nationwide record temperature of 41.5 °C (106.7 °F) was recorded in Grono, Graubünden.^[22]

United Kingdom[link]

The United Kingdom in general was suffering from a warm summer with temperatures well above average. However, Atlantic cyclones brought cool and wet weather for a short while at the end of July and very beginning of August before the temperatures started to increase substantially from 3 August onwards. Several weather records were broken in the United Kingdom, including the UK's highest recorded temperature 38.5 °C (101.3 °F) at Gravesend in Kent on 10 August. London also recorded 38.0 °C (100.4 °F). Scotland also broke its highest temperature record with 32.9 °C (91.2 °F) recorded in Greycrook in the Scottish borders on 9 August.^[23] According to the BBC around 2,000 more people than usual died in the United Kingdom during the 2003 heatwave.^[24]

Ireland[link]

The summer of 2003 was warmer than average in Ireland, but the heat was far less pronounced there than in the rest of Europe. August was by far the warmest, sunniest and driest month, with temperatures roughly 2°C above average. The highest temperature recorded was 30.3 °C (86.5 °F) at Belderrig, County Mayo on 8 August.^[25][26][27]

Effects on crops[link]

Crops which suffered most from drought were grown in Southern Europe.

Wheat[link]

The following shortfalls in wheat harvest occurred as a result of the long drought.^{[citation needed]}The long drought occurred because of the increasing temperature change which affects the whole globe.

• France – 20%
• Italy – 13%
• United Kingdom – 12%
• Ukraine – 75% (Unknown if affected by heatwave or an early freeze that year.)
• Moldova – 80%

Many other countries had shortfalls of 5–10%, and the EU total production was down by 10 million tonnes, or 10%.^{[citation needed]}

Grapes[link]

The heat wave greatly accelerated the ripening of grapes; also, the heat dehydrates the grapes, making for more concentrated juice. By mid-August, the grapes in certain vineyards had already reached their nominal sugar content, possibly resulting in 12°–12.5° wines (see alcoholic degree). Because of that, and also of the impending change to rainy weather, the harvest was started much earlier than usual (e.g. in mid-August for areas that are normally harvested in September).

It is predicted that the wines from 2003, although in scarce quantity, will have exceptional quality, especially in France. The heat wave made Hungary fare extremely well in the Vinalies 2003 International wine contest: a total of nine gold and nine silver medals were awarded to Hungarian winemakers.^[28]

Effects on the sea[link]

The anomalous overheating affecting the atmosphere also created anomalies on sea surface stratification in the Mediterranean Sea and on the surface currents as well. A seasonal current of the Central Mediterranean Sea, the Atlantic Ionian Stream (AIS), was affected by the warm temperatures, resulting in modifications in its path and intensity. The AIS is important for the reproduction biology of important pelagic commercial fish species, so the heatwave may have influenced indirectly the stocks of these species. Further studies will be addressed in this direction.^[29]

See also[link]

• Drought
• 2010 Northern Hemisphere summer heat wave
• 2006 European heat wave
• 2010 Sahel famine

References[link]

v t e Weather events in the United Kingdom Avalanches Lewes, 1836 Buachaille Etive Mòr, 2009 Coldwaves Winter of 1894–1895 Winter of 1946–1947 Winter of 1962–1963 Winter of 1990–1991 February 2009 snowfall Winter of 2009–2010 Winter of 2010–11 February 2012 Floods Bristol Channel, 1607 (disputed tsunami) Holmfirth, 1738, 1777, 1852, 1944 Strathspey, 1829 Sheffield, 1864 Thames, 1928 Thames, 1947 Lynmouth, 1952 North Sea, 1953 South England, 1968 UK, 2000 Glasgow, 2002 Boscastle, 2004 UK, 2007 North Sea, 2007 Morpeth, 2008 Sheffield, 2009 UK, 2009 Droughts and heatwaves 1906 1911 1955 1976 1990 2003 2006 2011 (Spring Autumn) 2012 Thunderstorms Widecombe-in-the-Moor, 1638 Tornadoes London, 1091 Great Malvern, 1761 Birmingham, 2005 London, 2006 West Midlands and Wales, 2011 Windstorms December 1287 November–December 1703 August 1848 October 1859 February 1871 December 1879 January 1881 (blizzard) October 1881 January 1968 October 1987 January 1990 December 1998 January 2007 December 2011 January 2012 See also Climate Drought

A heat wave is a prolonged period of excessively hot weather, which may be accompanied by high humidity. There is no universal definition of a heat wave;^[1] the term is 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 termed a heat wave in a cooler area if they are outside the normal climate pattern for that area.^[2] The term is applied both to routine weather variations and to extraordinary spells of heat 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.

Definitions[link]

The definition recommended by the World Meteorological Organization is 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.^[3]

A formal, peer-reviewed definition from the Glossary of Meteorology is:^[4]

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 region.

Temperature anomalies, March to May, 2007

In the Netherlands, a heat wave is defined as 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 heat wave 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).

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.^[5] 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 is ties in with humidity levels to determine a heat index threshold.^[6] 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, 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).^[7]

How they occur[link]

High pressure aloft 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. 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 middle layers of the atmosphere, is the high pressure area.

Summertime weather patterns are generally slower to change than in winter. As a result, this mid-level high pressure also moves slowly. Under high pressure, the air subsides (sinks) toward the surface. This sinking air acts as a dome capping the atmosphere.

This cap helps to trap heat instead of allowing it to lift. Without the lift there is little or no convection and therefore little or no convective clouds (cumulus clouds) with minimal chances for rain. The end result is a continual build-up of heat at the surface that we experience as a heat wave.^[8]

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 North-eastward resulting in a spell of hot and humid weather for much of the Eastern States.^[9]

In the Western Cape Province of South Africa, a heat wave can occur when a low pressure offshore and high pressure inland combine to form a Bergwind. The air warms as it descends from the Karoo interior, and the temperature will rise about 10 degrees 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.^[10][11]

Global warming boosts the probability of really extreme events, like heat waves, far more than it boosts more moderate events.^[12]

Health effects[link]

The Heat Index is a measure of how hot it really feels when relative humidity is factored with the actual air temperature. IMPORTANT: Since heat index values were devised for shady, light wind conditions, exposure to full sunshine can increase heat index values by up to 15°F. also, strong winds, particularly with very hot, dry air, can be extremely hazardous.

Hyperthermia, also known as heat stroke, becomes commonplace during periods of sustained high temperature and humidity. Sweating is absent from 84%–100% of those affected. 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.^[13]

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 stocking and elevating the affected legs with 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.

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 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.

Mortality[link]

Heat waves are the most lethal type of weather phenomenon, overall. 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.^[14] The average annual number of fatalities directly attributed to heat in the United States is about 400.^[15] The 1995 Chicago heat wave, one of the worst in US history, led to approximately 600 heat-related deaths over a period of five days.^[16] 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.^[17][18] 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." "Heat doesn't bother me much, but I worry about my neighbors," said one of his older respondents.^[19] 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.^[20] More than 70,000 Europeans died as a result of the 2003 European heat wave.^[21]

Underreporting and "Harvesting" effect

The number of heat fatalities is likely highly underreported due to lack of reports and misreports.^[15] 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 reduction in mortality suggests that heat affects especially those so ill that they "would have died in the short term anyway".^[22]

Psychological and sociological effects[link]

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.^[23]

Power outages[link]

Abnormally hot temperatures 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.^[24] 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 the power grid.

Wildfires[link]

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.^[25] High end farmlands have irrigation systems to back up crops with.

Physical damage[link]

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

History[link]

20th century[link]

1923/1924 - During a period of 160 such days from 31 October 1923 to 7 April 1924, the Western Australian town of Marble Bar set a world record for the most consecutive days above 100 °F (38 °C).^[26]

1936 - The 1936 North American heat wave during the Dust Bowl, followed one of the coldest winters on record—the 1936 North American cold wave. Massive heat waves across North America were persistent in the 1930s, many mid-Atlantic/Ohio valley states recorded their highest temperatures during July 1934. The longest continuous string of 100 °F (38 °C) or higher temperatures was reached for 101 days in Yuma, Arizona during 1937 and the highest temperatures ever reached in Canada were recorded in two locations in Saskatchewan in July 1937.

1950s - A prolonged severe drought and heat wave occurred in the early 1950s throughout the central and southern United States. In some areas it was drier than during the Dust Bowl and the heat wave in most areas was within the top five on record. The heat was particularly severe in 1954 with 22 days of temperatures exceeding 100 °F (38 °C) covering significant parts of eleven states. On July 14, the thermometer reached 117 °F (47 °C) at East St. Louis, Illinois, which remains the record highest temperature for that state.^[27][28][29]

1972 - The heat waves of 1972 in New York and Northeastern United States were significant. Almost 900 people perished; the heat conditions lasted almost 16 days, aggravated by very high humidity levels.

1976 - The 1976 United Kingdom heat wave was one of the hottest in living memory and was marked by constant blues skies from May until September when dramatic thunderstorms signalled the heat wave's end.

1980 - An estimated 10,000 people perished in the 1980 United States heat wave and drought, which impacted the central and eastern United States. Temperatures were highest in the southern plains. From June through September, temperatures remained above 90 °F (32 °C) all but two days in Kansas City, Missouri. The Dallas/Fort Worth area experienced 42 consecutive days with high temperatures above 100 °F (38 °C), with temperatures reaching 117 °F (47 °C) at Wichita Falls, Texas on June 28. Economic losses were $20 billion (1980 dollars).^[30]

1983 - During the Summer of 1983 temperatures over 100 °F (38 °C) were common across Iowa, Missouri, Illinois, Michigan, Wisconsin, Indiana, Ohio, Minnesota, Nebraska and certain parts of Kentucky; the summer of 1983 remains one of the hottest summers ever recorded in many of the states affected. The hundred-degree readings were accompanied by very dry conditions associated with drought affecting the Corn Belt States and Upper Midwest. The heat also affected the Southeastern U.S. and the Mid-Atlantic states as well that same summer. New York Times represented articles about the heat waves of 1983 affecting the central United States.^[31]

Temperature difference in Europe from the average during the European heat wave of 2003

1988 - intense heat spells in combination with the drought of 1988, reminiscent of the dust bowl years caused deadly results across the United States. Some 5,000 to 10,000 people perished because of constant heat across the United States although-according to many estimates-total death reports run as high as next to 17,000 deaths.^[32]

1995 - The 1995 Chicago heat wave produced record high dew point levels and heat indices in the Chicago area and Wisconsin. The lack of emergency cooling facilities and inadequate response from civic authorities to the senior population, particularly in lower income neighborhoods in Chicago and other Midwest cities, lead to many deaths.

1999 - a heat wave and drought in the eastern United States during the summer of 1999. Rainfall shortages resulted in worst drought on record for Maryland, Delaware, New Jersey, and Rhode Island. The state of West Viriginia was declared a disaster area. 3,810,000 acres (15,400 km²) were consumed by fire as of mid-August Record heat throughout the country resulted in 502 deaths nationwide.^[33][34]

21st century[link]

2000–2009[link]

• In early August 2001 an intense heatwave hit the eastern seaboard of the United States and neighboring southeastern Canada. For over a week, temperatures climbed above 35 °C (95 °F) combined with stifling high humidity. Newark, New Jersey tied its all-time record high temperature of 41 °C (106 °F) with a heat index of over 50 °C (122 °F).^[35]
• In April 2002 a summer-like heat wave in spring affected much of the Eastern United States.
• Nearly 35,000 people died in the European heat wave of 2003.^{[citation needed]} Much of the heat was concentrated in France, where nearly 15,000 people died^{[citation needed]}. In Portugal, the temperatures reached as high as 48 °C (118 °F) in the south.
• The European heat wave of 2006 was the second massive heat wave to hit the continent in four years, with temperatures rising to 40 °C (104 °F) in Paris; in Ireland, which has a moderate maritime climate, temperatures of over 32 °C (90 °F) were reported. Temperatures of 35 °C (95 °F) were reached in the Benelux and Germany (in some areas 38 °C (100 °F), while Great Britain recorded 37 °C (99 °F). Many heat records were broken (including the hottest ever July temperature in Great Britain) and many people who experienced the heat waves of 1976 and 2003 drew comparisons with them. Highest average July temperatures were recorded at many locations in Great Britain, Netherlands, Denmark, Sweden and Germany.
• The 2006 North American heat wave affected a wide area of the United States and parts of neighboring Canada during July and August 2006. Over 220 deaths were reported. Temperatures in some parts of South Dakota exceeded 115 °F (46 °C). Also, California experienced temperatures that were extraordinarily high, with records ranging from 100 to 130 °F (38 to 54 °C). On July 22, the County of Los Angeles recorded its highest temperature ever at 119 °F (48 °C). Humidity levels in California were also unusually high, although low compared with normal gulf coast/eastern seaboard summer humidity they were significant enough to cause widespread discomfort.^[36]
• The European heat wave of 2007 affected primarily south-eastern Europe during late June through August. Bulgaria experienced its hottest year on record, with previously unrecorded temperatures above 45 °C (113 °F). The 2007 Greek forest fires were associated with the heat wave.
• During the 2007 Asian heat wave, the Indian city of Datia experienced temperatures of 48 °C (118 °F).
• In January 2008, Alice Springs in Australia's Northern Territory recorded ten consecutive days of temperatures above 40 °C (104 °F) with the average temperature for that month being 39.8 °C (103.6 °F). In March 2008, Adelaide, South Australia experienced maximum temperatures of above 35 °C (95 °F) for fifteen consecutive days, seven days more than the previous longest stretch of 35 °C (95 °F) days. The March 2008 heat wave also included eleven consecutive days above 38 °C (100 °F).^[37] The heat wave was especially notable because it occurred in March, an autumn month, in which Adelaide averages only 2.3 days above 35 °C (95 °F).^[38]
• The eastern United States experienced an early Summer heat wave from June 6–10, 2008 with record temperatures.^[39] There was a heat wave in Southern California beginning late June,^[40] which contributed to widespread fires. On July 6, a renewed heat wave was forecast, which was expected to affect the entire state.^[41][42]
• In early 2009, Adelaide, South Australia was hit by a heat wave with temperatures reaching 40+ °C for six days in a row, while many rural areas experienced temperatures hovering around about mid 40s °C (mid 110s°F). Kyancutta on the Eyre Peninsula endured at least one day at 48 °C, with 46 and 47 being common in the hottest parts of the state. Melbourne, in neighbouring Victoria recorded 3 consecutive days over 43 °C (109 °F), and also recorded its highest ever temperature 8 days later in a secondary heatwave, with the mercury peaking at 46.4 °C (115.5 °F). During this heat wave Victoria suffered from large bushfires which claimed the lives of more than 210 people and destroyed more than 2,500 homes. There were also over half a million people without power as the heatwave blew transformers and the power grid was overloaded.
• In August 2009, Argentina experienced a period of unusual and exceptionally hot weather during August 24–30, during the Southern Hemisphere winter, just a month before Spring,^[43] when an unusual and unrecorded winter heat wave hit the country. A shot of tropical heat drawn unusually far southward hiked temperatures 22 degrees Celsius (40 degrees Fahreinheit) above normal in the city of Buenos Aires and across the northern-centre regions of the country. Several records were broken. Even though normal high temperatures for late August are in the lower 15 °C (59 °F), readings topped 30 °C (86 °F) degrees at midweek, then topped out above 32 °C (90 °F) degrees during the weekend.^[44] Temperatures hit 33.8 °C (92.8 °F) on 29 August and finally 34.6 °C (94.3 °F) on 30 August in Buenos Aires, making it the hottest day ever recorded in winter breaking the 1996 winter record of 33.7 °C (92.7 °F). In the city of Santa Fe, 38.3 °C (100.9 °F) degrees on 30 August was registered, notwithstanding the normal high in the upper 15 °C/60°Fs. As per the Meteorological Office of Argentina, August 2009 has been the warmest month during winter since official measurements began.^[45]

2010–Present[link]

• The Northern Hemisphere summer heat wave of 2010 affected many areas across the Northern Hemisphere, especially parts of Northeastern China and European Russia.
• Starting in May 2010, records were being set. On 26 May, at Mohenjo-daro, Sindh province in Pakistan a national record high temperature of 53.5 °C (128.3 °F) occurred.
• In June 2010, Eastern Europe experienced very warm conditions. Ruse, Bulgaria hit 36.6 °C (97.9 °F) on the 13th making it the warmest spot in Europe. Other records broken on the 13th include Vidin, Bulgaria at 35.8 °C (96.4 °F), Sandanski, Bulgaria hitting 35.5 °C (95.9 °F), Lovech and Pazardzhik, Bulgaria at 35.1 °C (95.2 °F) as well as the capital, Sofia, hitting 33.3 °C (91.9 °F). The heat came from the Sahara desert and was not associated with rain. This helped the situation with high water levels in that part of the continent.^[46] On the 14th, several cities were once again above the 35 °C (95 °F) mark even though they did not break records. The only cities in Bulgaria breaking records were Musala peak hitting 15.2 °C (59.4 °F) and Elhovo hitting 35.6 °C (96.1 °F).^[47] On the 15th, Ruse, Bulgaria peaked at 37.2 °C (99.0 °F). Although it was not a record, this was the highest temperature recorded in the country. Five Bulgarian cities broke records that day: Ahtopol hit 28.6 °C (83.5 °F), Dobrich was 33.8 °C (92.8 °F), Karnobat hit 34 °C (93 °F), Sliven hit 35 °C (95 °F) and Elhovo recorded 36.1 °C (97.0 °F).^[48]
• From July 4 to July 9, 2010, the majority of the American East Coast, from the Carolinas to Maine, was gripped in a severe heat wave. Philadelphia, New York, Baltimore, Washington, Raleigh, and even Boston eclipsed 100 °F (38 °C). Many records were broken, some of which dated back to the 19th century, including Wilmington, Delaware's temperature of 103 °F (39 °C) on Wednesday, July 7, which broke the record of 97 °F (36 °C) from 1897. Philadelphia and New York eclipsed 100 °F (38 °C) for the first time since 2001. Fredrick, Maryland, and Newark, New Jersey, among others topped the century mark (37.8 Celsius) for four days in a row.^[49]
• The UK declared a heatwave, MetOffice Level 2/4, on 9 July 2010 for South East England and East Anglia. This was after temperatures reached 31.0 degrees Celsius in London and night-time temperatures levelled around 21 degrees Celsius.
• In the Japanese heat wave of 2010 which began on July 16, temperatures reaching as high as 35.0 °C (95.0 °F) were reported in many Japanese cities, for 33 days in Kyoto, 29 days in Tottori and 25 days in Osaka. According to a Japan Meteorological Agency report, some of these cities recorded the highest temperature in September since 1868, reaching 39.9 °C (103.8 °F) in Kyotanabe, Kyoto, 39.1 °C (102.4 °F) in Gujo, Gifu, and higher than 30.0 °C (86.0 °F) in 653 cities and 35.0 °C (95.0 °F) in 128 cities during September 4 and 5, 2010.^{[citation needed]}
• The 2011 North American heat wave brought record heat to the Midwestern United States, Eastern Canada, and much of the Eastern Seaboard.
• A record-breaking heat wave hit Southwestern Asia in late July and early August 2011, with temperatures in Iraq exceeding 120 °F (49 °C),^[50] and an "asphalt-melting, earth-parching, brain-scrambling heat of midsummer" in Tbilisi, Georgia.^[51] The Iraqis were further challenged by pressure to fast during Ramadan, despite heat of 124 °F (51 °C) in Bagdad and 126 °F (52 °C) in Diwaniya on 4 August.^[50] The extreme heat inspired conspiracy theories of the government corruption in Iraq and retaliation from the United States government;^[50] and, in Georgia, the Apocalypse, mutant locusts caused by Chernobyl, snakes imported by unseen enemies, and sun spots.^[51]
• Most parts of the United Kingdom experienced an Indian summer between September and October 2011. The heat wave resulted in a new record high temperature for October at 30°C.^[52]

Land surface temperatures of March 8–15, 2012. Land surface temperatures are distinct from the air temperatures that meteorological stations typically measure.

• In March 2012, one of the greatest heat waves was observed in many regions of North America. First very warm air pushed northward west of the Great Lakes region, and subsequently spread eastward. This air mass movement was propelled by an unusually intense low level southerly jet that stretched from Louisiana to western Wisconsin. Once this warm surge inundated the area, a remarkably prolonged period of record setting temperatures ensued.^[53] NOAA's National Climate Data Center reported that over 7000 daily record high temperatures were broken over the U.S. from 1 March thru 27 March.^[53] In some places the temperature exceeded 30 °C (86 °F) with anomalies up to +22°C. Temperature records across much of southern Canada were also demolished.^[54]
• In March, 2012, the United Kingdom experienced a heat wave with temperature anomalies of +10 °C in many places.^[55]

See also[link]

• Cold wave
• Heat burst
• List of severe weather phenomena
• Urban heat island

Notes[link]

• 'Heat Dome' seals in sweltering temperatures
• Klinenberg, Eric (2002). Heat Wave: A Social Autopsy of Disaster in Chicago. Chicago: University of Chicago Press. ISBN 0-226-44321-3. 

External links[link]

• FEMA: Extreme Heat
• Hot Weather Tips
• WeatherBug Weather Wrap
• Social & Economic Costs of Temperature Extremes from "NOAA Socioeconomics" website initiative
• Study: Global Warming to Bring Increased Heat Waves to U.S. – video report by Democracy Now!
• Wu, Zhiwei; et al. (2012). "Heat wave frequency variability over North America: Two distinct leading modes". J. Geophys. Res. 117 (D02102). DOI:10.1029/2011JD016908. http://www.agu.org/pubs/crossref/2012/2011JD016908.shtml.