Heat wave

Heat wave

Overview
A heat wave is a prolonged period of excessively hot weather, which may be accompanied by high humidity
Humidity
Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...

. There is no universal definition of a heat wave; the term is relative to the usual weather in the area. 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
Climate
Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...

 pattern for that area.
The term is applied both to routine weather variations and to extraordinary spells of heat which may occur only once a century.
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Encyclopedia
A heat wave is a prolonged period of excessively hot weather, which may be accompanied by high humidity
Humidity
Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...

. There is no universal definition of a heat wave; the term is relative to the usual weather in the area. 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
Climate
Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...

 pattern for that area.
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
Hyperthermia
Hyperthermia is an elevated body temperature due to failed thermoregulation. Hyperthermia occurs when the body produces or absorbs more heat than it can dissipate...

, and widespread power outages due to increased use of air conditioning.

Definitions


The definition recommended by the World Meteorological Organization
World Meteorological Organization
The World Meteorological Organization is an intergovernmental organization with a membership of 189 Member States and Territories. It originated from the International Meteorological Organization , which was founded in 1873...

 is when the daily maximum temperature of more than five consecutive days exceeds the average maximum temperature by 5 Celsius degrees (9 Fahrenheit degrees), the normal period being 1961–1990.

A formal, peer-reviewed
Peer review
Peer review is a process of self-regulation by a profession or a process of evaluation involving qualified individuals within the relevant field. Peer review methods are employed to maintain standards, improve performance and provide credibility...

 definition from the Glossary of Meteorology is:
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.



In the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

, a heat wave is defined as period of at least 5 consecutive days in which the maximum temperature in De Bilt
De Bilt
De Bilt is a municipality and a town in the Netherlands, in the province of Utrecht.-Population centres :The municipality of De Bilt consists of the following cities, towns, villages and/or districts: Bilthoven, De Bilt, Groenekan, Hollandsche Rading, Maartensdijk, Westbroek...

 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
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

 and Luxembourg
Luxembourg
Luxembourg , officially the Grand Duchy of Luxembourg , is a landlocked country in western Europe, bordered by Belgium, France, and Germany. It has two principal regions: the Oesling in the North as part of the Ardennes massif, and the Gutland in the south...

.

In Denmark
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. 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.

In the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, 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. In the Northeast
Northeastern United States
The Northeastern United States is a region of the United States as defined by the United States Census Bureau.-Composition:The region comprises nine states: the New England states of Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island and Vermont; and the Mid-Atlantic states of New...

, 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. The same does not apply to drier climates. A heat storm
Heat Storm
A heat storm, as defined by the California Energy Commission, is what most would refer to as a heat wave. According to the commission website, heat storms occur when the temperature reaches 100°F for three or more consecutive days over a wide area .Normal hot temperatures cause electricity demand...

 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
National Weather Service
The National Weather Service , once known as the Weather Bureau, is one of the six scientific agencies that make up the National Oceanic and Atmospheric Administration of the United States government...

 issues heat advisories
Heat advisory
A Heat Advisory is issued by the National Weather Service of the United States within 12 hours of the heat index reaching one of two criteria levels. A warning will be issued if there is a heat index of at least 105°F but less than 115°F for less than 3 hours per day or if nighttime low...

 and excessive heat warning
Excessive heat warning
An Excessive Heat Warning is issued by the National Weather Service of the United States within 12 hours of the heat index reaching one of two criteria levels. A warning will be issued if there is a heat index of at least 105°F for more than 3 hours per day for 2 consecutive days, or if the heat...

s 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).

Incidence


Heat waves often occur during the Dog Days
Dog Days
"Dog Days" are the hottest, most sultry days of summer. In the Northern Hemisphere, the dog days of summer are most commonly experienced in the months of July and August, which typically observe the warmest summer temperatures. In the Southern Hemisphere, they typically occur in January and...

 of summer; indeed the French term canicule, denoting the general phenomenon of a heat wave, derives from the Italian canicula applied to the star Sirius
Sirius
Sirius is the brightest star in the night sky. With a visual apparent magnitude of −1.46, it is almost twice as bright as Canopus, the next brightest star. The name "Sirius" is derived from the Ancient Greek: Seirios . The star has the Bayer designation Alpha Canis Majoris...

, also known as the "Dog Star."

Some regions of the globe are more susceptible to heat waves than others, typically inland desert, semidesert, and Mediterranean-type climates
Mediterranean climate
A Mediterranean climate is the climate typical of most of the lands in the Mediterranean Basin, and is a particular variety of subtropical climate...

.

How they occur


In the summer in warm climates, an area of high pressure with little or no rain or clouds, the air and ground easily heats to excess. A static high pressure area can impose a very persistent heat wave.

The position of the jet stream
Jet stream
Jet streams are fast flowing, narrow air currents found in the atmospheres of some planets, including Earth. The main jet streams are located near the tropopause, the transition between the troposphere and the stratosphere . The major jet streams on Earth are westerly winds...

 allows air on one side to be considerably warmer than the other side. Heat waves are far more common and more severe on the warm side and at times an unusual position of the jet stream places unusual warmth in an unusual place for hot weather, and imposes a heat wave. El Niño
El Niño-Southern Oscillation
El Niño/La Niña-Southern Oscillation, or ENSO, is a quasiperiodic climate pattern that occurs across the tropical Pacific Ocean roughly every five years...

 and La Niña (opposite reaction to El Niño) can severely disrupt the positions of the jet streams.

Large desert zones and dry areas are more likely to get extreme heat because there is rarely any high cloud cover with very low humidity.

Winds from hot deserts typically push hot, dry air towards areas normally cooler than during a heat wave. During the summer an area that has no geographic features that might cool winds that originate in the hot deserts get little mitigation, especially near the summer solstice when long days and a high sun would create warm conditions even without the transport of hot air from other locations. Should such a hot air mass travel above a large body of water, as a sirocco
Sirocco
Sirocco, scirocco, , jugo or, rarely, siroc is a Mediterranean wind that comes from the Sahara and reaches hurricane speeds in North Africa and Southern Europe. It is known in North Africa by the Arabic word qibli or ghibli Sirocco, scirocco, , jugo or, rarely, siroc is a Mediterranean wind...

 of Saharan origin crossing the Mediterranean sea, it likely picks up much water vapor with a reduction in temperature but far greater humidity
Humidity
Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...

 that makes the original desert air little less moderate as demonstrated in a high heat index
Heat index
The heat index is an index that combines air temperature and relative humidity in an attempt to determine the human-perceived equivalent temperature — how hot it feels, termed the felt air temperature. The human body normally cools itself by perspiration, or sweating, which evaporates and carries...

. Heat waves can also come from air originating over tropical seas penetrating far into the middle latitudes heating further overland, as often occurs in the eastern United States and southeastern Canada. The heat island created by dense urbanization of large cities only exacerbate heat waves because of the weakness of night-time cooling.

Health effects


Hyperthermia
Hyperthermia
Hyperthermia is an elevated body temperature due to failed thermoregulation. Hyperthermia occurs when the body produces or absorbs more heat than it can dissipate...

, 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., diuretic
Diuretic
A diuretic provides a means of forced diuresis which elevates the rate of urination. There are several categories of diuretics. All diuretics increase the excretion of water from bodies, although each class does so in a distinct way.- Medical uses :...

s, anticholinergic
Anticholinergic
An anticholinergic agent is a substance that blocks the neurotransmitter acetylcholine in the central and the peripheral nervous system. An example of an anticholinergic is dicycloverine, and the classic example is atropine....

s, antipsychotic
Antipsychotic
An antipsychotic is a tranquilizing psychiatric medication primarily used to manage psychosis , particularly in schizophrenia and bipolar disorder. A first generation of antipsychotics, known as typical antipsychotics, was discovered in the 1950s...

s, and antihypertensive
Antihypertensive
The antihypertensives are a class of drugs that are used to treat hypertension . Evidence suggests that reduction of the blood pressure by 5 mmHg can decrease the risk of stroke by 34%, of ischaemic heart disease by 21%, and reduce the likelihood of dementia, heart failure, and mortality from...

s) that interfere with the body's ability to dissipate heat.

Heat edema
Edema
Edema or oedema ; both words from the Greek , oídēma "swelling"), formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin or in one or more cavities of the body that produces swelling...

 presents as a transient swelling of the hands, feet, and ankles and is generally secondary to increased aldosterone
Aldosterone
Aldosterone is a hormone that increases the reabsorption of sodium ions and water and the release of potassium in the collecting ducts and distal convoluted tubule of the kidneys' functional unit, the nephron. This increases blood volume and, therefore, increases blood pressure. Drugs that...

 secretion
Secretion
Secretion is the process of elaborating, releasing, and oozing chemicals, or a secreted chemical substance from a cell or gland. In contrast to excretion, the substance may have a certain function, rather than being a waste product...

, which enhances water retention. When combined with peripheral vasodilation and venous
Vein
In the circulatory system, veins are blood vessels that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart...

 stasis
Stasis (medicine)
In medicine, stasis is the state in which the normal flow of a body liquid stops, for example the flow of blood through vessels or of intestinal contents through the digestive tract....

, 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
Miliaria
Miliaria is a skin disease marked by small and itchy rashes. Miliaria is a common ailment in hot and humid conditions, such as in the tropics and during the summer season...

, also known as prickly heat, is a maculopapular rash
Maculopapular rash
A maculopapular rash is a type of rash characterized by a flat, red area on the skin that is covered with small confluent bumps. The term "maculopapular" is a compound: macules are small, flat discolored spots on the surface of the skin; and papules are small, raised bumps...

 accompanied by acute inflammation and blocked sweat ducts. The sweat ducts may become dilated and may eventually rupture, producing small pruritic vesicles on an erythema
Erythema
Erythema is redness of the skin, caused by hyperemia of the capillaries in the lower layers of the skin. It occurs with any skin injury, infection, or inflammation...

tous 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
Dermatitis
-Etymology:Dermatitis derives from Greek derma "skin" + -itis "inflammation" and genetic disorder.-Terminology:There are several different types of dermatitis. The different kinds usually have in common an allergic reaction to specific allergens. The term may describe eczema, which is also called...

 or a secondary bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

l 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
Desquamation
Desquamation , also called skin peeling, is the shedding of the outermost membrane or layer of a tissue, such as the skin.-Skin:Normal, nonpathologic desquamation of the skin occurs when keratinocytes, after moving apically over about 14 days, are individually shed unnoticeably...

 skin. The associated itching may be treated with topical or systemic antihistamines. If infection occurs a regimen of antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...

s is required.

Heat cramps
Heat cramps
Heat cramps are muscle spasms that result from loss of large amount of salt and water through exercise. Heat cramps are associated with cramping in the abdomen, arms and calves. This can be caused by inadequate consumption of fluids or electrolytes. Frequently, they don't occur until sometime...

 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
Hyponatremia
Hyponatremia is an electrolyte disturbance in which the sodium concentration in the serum is lower than normal. In the vast majority of cases, hyponatremia occurs as a result of excess body water diluting the serum sodium and is not due to sodium deficiency. Sodium is the dominant extracellular...

 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
Intravenous therapy
Intravenous therapy or IV therapy is the infusion of liquid substances directly into a vein. The word intravenous simply means "within a vein". Therapies administered intravenously are often called specialty pharmaceuticals...

 isotonic fluids. The many sport drinks on the market are a good source of electrolyte
Electrolyte
In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....

s and are readily accessible.

Heat syncope
Heat syncope
Heat syncope is fainting as a result of overheating . It is another stage in the same process as heat stroke, it occurs under similar conditions, and it is not distinguished from the latter by some authorities...

 is related to heat exposure that produces orthostatic hypotension
Orthostatic hypotension
Orthostatic hypotension, also known as postural hypotension, orthostasis, and colloquially as head rush or dizzy spell, is a form of hypotension in which a person's blood pressure suddenly falls when the person stands up or stretches. The decrease is typically greater than 20/10 mm Hg, and may be...

. This hypotension can precipitate a near-syncopal episode. Heat syncope is believed to result from intense sweating, which leads to dehydration
Dehydration
In physiology and medicine, dehydration is defined as the excessive loss of body fluid. It is literally the removal of water from an object; however, in physiological terms, it entails a deficiency of fluid within an organism...

, 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
Oral rehydration therapy
Oral rehydration therapy is a simple treatment for dehydration associated with diarrhoea, particularly gastroenteritis or gastroenteropathy, such as that caused by cholera or rotavirus. ORT consists of a solution of salts and sugars which is taken by mouth...

 (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
Hyperthermia
Hyperthermia is an elevated body temperature due to failed thermoregulation. Hyperthermia occurs when the body produces or absorbs more heat than it can dissipate...

). 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
Dizziness
Dizziness refers to an impairment in spatial perception and stability. The term is somewhat imprecise. It can be used to mean vertigo, presyncope, disequilibrium, or a non-specific feeling such as giddiness or foolishness....

, tachycardia
Tachycardia
Tachycardia comes from the Greek words tachys and kardia . Tachycardia typically refers to a heart rate that exceeds the normal range for a resting heart rate...

, malaise
Malaise
Malaise is a feeling of general discomfort or uneasiness, of being "out of sorts", often the first indication of an infection or other disease. Malaise is often defined in medicinal research as a "general feeling of being unwell"...

, and myalgia
Myalgia
Myalgia means "muscle pain" and is a symptom of many diseases and disorders. The most common causes are the overuse or over-stretching of a muscle or group of muscles. Myalgia without a traumatic history is often due to viral infections...

. 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


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
Tropical cyclone
A tropical cyclone is a storm system characterized by a large low-pressure center and numerous thunderstorms that produce strong winds and heavy rain. Tropical cyclones strengthen when water evaporated from the ocean is released as the saturated air rises, resulting in condensation of water vapor...

. The average annual number of fatalities directly attributed to heat in the United States is about 400. The 1995 Chicago heat wave
1995 Chicago heat wave
The 1995 Chicago heat wave was a heat wave which led to approximately 750 heat-related deaths in Chicago over a period of five days. Eric Klinenberg, author of the 2002 book Heat Wave: A Social Autopsy of Disaster in Chicago, has noted that in the United States, the loss of human life in hot spells...

, one of the worst in US history, led to approximately 600 heat-related deaths over a period of five days. 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
Lightning
Lightning is an atmospheric electrostatic discharge accompanied by thunder, which typically occurs during thunderstorms, and sometimes during volcanic eruptions or dust storms...

, rain, flood
Flood
A flood is an overflow of an expanse of water that submerges land. The EU Floods directive defines a flood as a temporary covering by water of land not normally covered by water...

s, hurricanes, and tornado
Tornado
A tornado is a violent, dangerous, rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. They are often referred to as a twister or a cyclone, although the word cyclone is used in meteorology in a wider...

es.
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. 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.

Underreporting and "Harvesting" effect
The number of heat fatalities is likely highly underreported due to lack of reports and misreports. Part of the mortality observed during a heat wave, however, can be attributed to a so-called "harvesting effect
Mortality displacement
Mortality displacement denotes a temporal shift in the rate of mortality in a given population, usually attributable to environmental phenomena such as heat waves or cold spells....

", 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".

Psychological and sociological effects


In addition to physical stress
Stress (biology)
Stress is a term in psychology and biology, borrowed from physics and engineering and first used in the biological context in the 1930s, which has in more recent decades become commonly used in popular parlance...

, excessive heat causes psychological stress, to a degree which affects performance, and is also associated with an increase in violent crime.

Power outages


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
2006 North American heat wave
The 2006 North American heat wave spread throughout most of the United States and Canada beginning on July 15, 2006, killing at least 225 people. That day the temperature reached 117 °F in Pierre, South Dakota, with many places in South Dakota that hit well into the 120s. A 130 degree...

, thousands of homes and businesses went without power, especially in California. In Los Angeles, electrical transformer
Transformer
A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field...

s failed, leaving thousands without power for as long as five days.
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


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 3010 square kilometres (743,786.5 acre) of forest and 440 square kilometres (108,726.3 acre) of agricultural land and causing an estimated
Euro
The euro is the official currency of the eurozone: 17 of the 27 member states of the European Union. It is also the currency used by the Institutions of the European Union. The eurozone consists of Austria, Belgium, Cyprus, Estonia, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg,...

1 billion worth of damage. High end farmlands have irrigation systems to back up crop
Crop (agriculture)
A crop is a non-animal species or variety that is grown to be harvested as food, livestock fodder, fuel or for any other economic purpose. Major world crops include maize , wheat, rice, soybeans, hay, potatoes and cotton. While the term "crop" most commonly refers to plants, it can also include...

s with.

Physical damage


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
2006 North American heat wave
The 2006 North American heat wave spread throughout most of the United States and Canada beginning on July 15, 2006, killing at least 225 people. That day the temperature reached 117 °F in Pierre, South Dakota, with many places in South Dakota that hit well into the 120s. A 130 degree...

 article about heat waves causing physical damage.

20th century


During a period of 160 such days from 31 October 1923 to 7 April 1924, the Western Australian
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...

 town of Marble Bar
Marble Bar, Western Australia
-North Pole:An ironically named locality nearby is known as North Pole , no doubt for its heat. It is the location of rock formations considered to have evidence that puts the origin of life on earth back to 3,400–3,500 mya, due to stromatolites in particular rock sequences...

 set a world record for the most consecutive days above 100 °F (37.8 °C).

The 1936 North American heat wave during the Dust Bowl
Dust Bowl
The Dust Bowl, or the Dirty Thirties, was a period of severe dust storms causing major ecological and agricultural damage to American and Canadian prairie lands from 1930 to 1936...

, 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 (37.8 °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
Saskatchewan
Saskatchewan is a prairie province in Canada, which has an area of . Saskatchewan is bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, and on the south by the U.S. states of Montana and North Dakota....

 in July 1937.

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 (37.8 °C) covering significant parts of eleven states. On July 14, the thermometer reached 117 °F (47.2 °C) at East St. Louis, Illinois
East St. Louis, Illinois
East St. Louis is a city located in St. Clair County, Illinois, USA, directly across the Mississippi River from St. Louis, Missouri in the Metro-East region of Southern Illinois. As of the 2010 census, the city had a total population of 27,006, less than one-third of its peak of 82,366 in 1950...

, which remains the record highest temperature for that state.

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.

The 1976 United Kingdom heat wave
1976 United Kingdom heat wave
The summer of 1976 was the hottest summer in the UK since records began. As well as the heat, Britain was in the middle of a severe drought.-Heatwave and drought effects:The temperature reached 80°F every day between 22 June and 16 July...

 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.

An estimated 10,000 people perished in the 1980 United States heat wave
1980 United States heat wave
The 1980 United States Heat Wave was a period of intense heat and drought that wreaked havoc on much of the midwestern United States throughout the summer of 1980. It is among the most devastating natural disasters in terms of deaths and destruction in U.S...

 and drought, which impacted the central and eastern United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. Temperatures were highest in the southern plains. From June through September, temperatures remained above 90 °F (32.2 °C) all but two days in Kansas City, Missouri
Kansas City, Missouri
Kansas City, Missouri is the largest city in the U.S. state of Missouri and is the anchor city of the Kansas City Metropolitan Area, the second largest metropolitan area in Missouri. It encompasses in parts of Jackson, Clay, Cass, and Platte counties...

. The Dallas/Fort Worth area experienced 42 consecutive days with high temperatures above 100 °F (37.8 °C), with temperatures reaching 117 °F (47.2 °C) at Wichita Falls, Texas
Wichita Falls, Texas
Wichita 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,...

 on June 28. Economic losses were $20 billion (1980 dollars).

During another heat wave in the Summer of 1983 temperatures over 100 °F (37.8 °C) were common across Iowa
Iowa
Iowa is a state located in the Midwestern United States, an area often referred to as the "American Heartland". It derives its name from the Ioway people, one of the many American Indian tribes that occupied the state at the time of European exploration. Iowa was a part of the French colony of New...

, Missouri
Missouri
Missouri is a US state located in the Midwestern United States, bordered by Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas and Nebraska. With a 2010 population of 5,988,927, Missouri is the 18th most populous state in the nation and the fifth most populous in the Midwest. It...

, Illinois
Illinois
Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...

, Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....

, Wisconsin
Wisconsin
Wisconsin is a U.S. state located in the north-central United States and is part of the Midwest. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin's capital is...

, Indiana
Indiana
Indiana is a US state, admitted to the United States as the 19th on December 11, 1816. It is located in the Midwestern United States and Great Lakes Region. With 6,483,802 residents, the state is ranked 15th in population and 16th in population density. Indiana is ranked 38th in land area and is...

, Ohio
Ohio
Ohio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...

, Minnesota
Minnesota
Minnesota 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...

, Nebraska
Nebraska
Nebraska is a state on the Great Plains of the Midwestern United States. The state's capital is Lincoln and its largest city is Omaha, on the Missouri River....

 and certain parts of Kentucky
Kentucky
The Commonwealth of Kentucky is a state located in the East Central United States of America. As classified by the United States Census Bureau, Kentucky is a Southern state, more specifically in the East South Central region. Kentucky is one of four U.S. states constituted as a commonwealth...

; to this day the summer of 1983 remains on record as 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
Corn Belt
The Corn Belt is a region of the Midwestern United States where corn has, since the 1850s, been the predominant crop, replacing the native tall grasses. By 1950, 99% of the corn was grown from hybrids. Most corn is fed to livestock, especially hogs and poultry. In recent decades soybeans have...

 and Upper Midwest
Upper Midwest
The Upper Midwest is a region in the northern portion of the U.S. Census Bureau's Midwestern United States. It is largely a sub-region of the midwest. Although there are no uniformly agreed-upon boundaries, the region is most commonly used to refer to the states of Minnesota, Wisconsin, and...

. The heat also affected the Southeastern U.S. and the Mid-Atlantic states
Mid-Atlantic States
The Mid-Atlantic states, also called middle Atlantic states or simply the mid Atlantic, form a region of the United States generally located between New England and the South...

 as well that same summer. New York Times represented articles about the heat waves of 1983 affecting the central United States.

During 1988 intense heat spells in combination with the drought of 1988 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.

The 1995 Chicago heat wave
1995 Chicago heat wave
The 1995 Chicago heat wave was a heat wave which led to approximately 750 heat-related deaths in Chicago over a period of five days. Eric Klinenberg, author of the 2002 book Heat Wave: A Social Autopsy of Disaster in Chicago, has noted that in the United States, the loss of human life in hot spells...

 produced record high dew point levels and heat indices in the Chicago area and Wisconsin
Wisconsin
Wisconsin is a U.S. state located in the north-central United States and is part of the Midwest. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin's capital is...

. 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.

The summer of 1999 saw a devastating heat wave and drought in the eastern United States. 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. 3810000 acres (15,418.5 km²) were consumed by fire as of mid-Aug. Record heat throughout the country resulted in 502 deaths nationwide.

2000–2009

  • In early August 2001 an intense heatwave hit the eastern seaboard of the United States
    United States
    The United States of America is a federal constitutional republic comprising fifty states and a federal district...

     and neighboring southeastern Canada
    Canada
    Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

    . For over a week, temperatures climbed above 35 °C (95 °F) combined with stifling high humidity. Newark, New Jersey
    Newark, New Jersey
    Newark is the largest city in the American state of New Jersey, and the seat of Essex County. As of the 2010 United States Census, Newark had a population of 277,140, maintaining its status as the largest municipality in New Jersey. It is the 68th largest city in the U.S...

     tied its all-time record high temperature of 41 °C (105.8 °F) with a heat index
    Heat index
    The heat index is an index that combines air temperature and relative humidity in an attempt to determine the human-perceived equivalent temperature — how hot it feels, termed the felt air temperature. The human body normally cools itself by perspiration, or sweating, which evaporates and carries...

     of over 50 °C (122 °F).
  • In April 2002 a summer-like heat wave in spring affected much of the Eastern United States
    Eastern United States
    The Eastern United States, the American East, or simply the East is traditionally defined as the states east of the Mississippi River. The first two tiers of states west of the Mississippi have traditionally been considered part of the West, but can be included in the East today; usually in...

    .
  • Nearly 35,000 people died in the European heat wave of 2003
    2003 European heat wave
    The 2003 European heat wave was 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 Southern Europe...

    . Much of the heat was concentrated in France, where nearly 15,000 people died . 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 (89.6 °F) were reported. Temperatures of 35 °C (95 °F) were reached in the Benelux
    Benelux
    The Benelux is an economic union in Western Europe comprising three neighbouring countries, Belgium, the Netherlands, and Luxembourg. These countries are located in northwestern Europe between France and Germany...

     and Germany (in some areas 38 °C (100.4 °F), while Great Britain recorded 37 °C (98.6 °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
    2006 North American heat wave
    The 2006 North American heat wave spread throughout most of the United States and Canada beginning on July 15, 2006, killing at least 225 people. That day the temperature reached 117 °F in Pierre, South Dakota, with many places in South Dakota that hit well into the 120s. A 130 degree...

     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 (46.1 °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
    Los Angeles County, California
    Los Angeles County is a county in the U.S. state of California. As of 2010 U.S. Census, the county had a population of 9,818,605, making it the most populous county in the United States. Los Angeles County alone is more populous than 42 individual U.S. states...

     recorded its highest temperature ever at 119 °F (48.3 °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.
  • The European heat wave of 2007
    2007 European heat wave
    The 2007 European heatwave was a heat wave that affected most of Southern Europe and the Balkans. The phenomenon began affecting Italy and Turkey on June 17 and expanded into Greece and the rest of the Balkans, Hungary and Ukraine on June 18.-June 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
    2007 Greek forest fires
    The 2007 Greek forest fires were a series of massive forest fires that broke out in several areas across Greece throughout the summer of 2007. The most destructive and lethal infernos broke out on August 23, expanded rapidly and raged out of control until August 27, until they were put out in early...

     were associated with the heat wave.
  • During the 2007 Asian heat wave
    2007 Asian heat wave
    The 2007 Asian heat wave affected the South Asian countries of India, Pakistan, Bangladesh, and Nepal, as well as Russia, Japan and the People's Republic of China. The heat wave ran during the months of May and June, with continues to September in Japan....

    , the Indian city of Datia
    Datia
    Datia is a small rural town and a municipality in Datia district in the state of Madhya Pradesh, India. It is the administrative center of Datia District. It was formerly the seat of the eponymous princely state in the British Raj. Datia is situated near Gwalior and on the border with Uttar...

     experienced temperatures of 48 °C (118.4 °F).
  • In January 2008, Alice Springs in Australia's Northern Territory
    Northern Territory
    The Northern Territory is a federal territory of Australia, occupying much of the centre of the mainland continent, as well as the central northern regions...

     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
    South Australia
    South Australia is a state of Australia in the southern central part of the country. It covers some of the most arid parts of the continent; with a total land area of , it is the fourth largest of Australia's six states and two territories.South Australia shares borders with all of the mainland...

     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 (100.4 °F). 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).
  • The eastern United States experienced an early Summer heat wave from June 6–10, 2008 with record temperatures. There was a heat wave in Southern California beginning late June, which contributed to widespread fires. On July 6, a renewed heat wave was forecast, which was expected to affect the entire state.
  • In early 2009, Adelaide
    Adelaide
    Adelaide is the capital city of South Australia and the fifth-largest city in Australia. Adelaide has an estimated population of more than 1.2 million...

    , South Australia
    South Australia
    South Australia is a state of Australia in the southern central part of the country. It covers some of the most arid parts of the continent; with a total land area of , it is the fourth largest of Australia's six states and two territories.South Australia shares borders with all of the mainland...

     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
    Melbourne
    Melbourne is the capital and most populous city in the state of Victoria, and the second most populous city in Australia. The Melbourne City Centre is the hub of the greater metropolitan area and the Census statistical division—of which "Melbourne" is the common name. As of June 2009, the greater...

    , in neighbouring Victoria
    Victoria (Australia)
    Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....

     recorded 3 consecutive days over 43 °C (109.4 °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
    Argentina
    Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

     experienced a period of unusual and exceptionally hot weather during August 24–30, during the Southern Hemisphere winter, just a month before Spring, when an unusual and unrecorded winter heat wave
    August 2009 Argentine winter heat wave
    The 2009 Argentine winter heat wave was a period of unusual and exceptionally hot weather that arrived at the end of the winter on August 2009 in Argentina. Several provinces of the country were most affected. Several records were broken...

     hit the country. A shot of tropical heat
    Heat
    In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...

     drawn unusually far southward hiked temperatures 22 degrees above normal in the city of Buenos Aires
    Buenos Aires
    Buenos Aires is the capital and largest city of Argentina, and the second-largest metropolitan area in South America, after São Paulo. It is located on the western shore of the estuary of the Río de la Plata, on the southeastern coast of the South American continent...

     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 (89.6 °F) degrees during the weekend. 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
    Santa Fe, Argentina
    Santa Fe is the capital city of province of Santa Fe, Argentina. It sits in northeastern Argentina, near the junction of the Paraná and Salado rivers. It lies opposite the city of Paraná, to which it is linked by the Hernandarias Subfluvial Tunnel. The city is also connected by canal with the...

    , 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.

2010–today

  • The Northern Hemisphere summer heat wave of 2010 affected many areas across the Northern Hemisphere
    Northern Hemisphere
    The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...

    , especially parts of Northeastern China and Southeastern Russia
    Russia
    Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

    .
  • In June 2010, Eastern Europe
    Eastern Europe
    Eastern Europe is the eastern part of Europe. The term has widely disparate geopolitical, geographical, cultural and socioeconomic readings, which makes it highly context-dependent and even volatile, and there are "almost as many definitions of Eastern Europe as there are scholars of the region"...

     experienced very warm conditions. Ruse, Bulgaria hit 36.6 °C (97.9 °F) on the 13th making it the warmest spot in Europe
    Europe
    Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

    . Other records broken on the 13th include Vidin
    Vidin
    Vidin is a port town on the southern bank of the Danube in northwestern Bulgaria. It is close to the borders with Serbia and Romania, and is also the administrative centre of Vidin Province, as well as of the Metropolitan of Vidin...

    , Bulgaria
    Bulgaria
    Bulgaria , officially the Republic of Bulgaria , is a parliamentary democracy within a unitary constitutional republic in Southeast Europe. The country borders Romania to the north, Serbia and Macedonia to the west, Greece and Turkey to the south, as well as the Black Sea to the east...

     at 35.8 °C (96.4 °F), Sandanski
    Sandanski
    -Municipality:Sandanski is the seat of Sandanski municipality , which includes the following 54 places:-Honour:Sandanski Point on Livingston Island in the South Shetland Islands, Antarctica is named after the town of Sandanski....

    , Bulgaria hitting 35.5 °C (95.9 °F), Lovech
    Lovech
    Lovech is a town in north-central Bulgaria with a population of 36,296 as of February 2011. It is the administrative centre of the Lovech Province and of the subordinate Lovech Municipality. The town is located about 150 km northeast from the capital city of Sofia...

     and Pazardzhik
    Pazardzhik
    Pazardzhik is a city situated along the banks of the Maritsa river, Southern Bulgaria. It is the capital of Pazardzhik Province and centre for the homonymous Pazardzhik Municipality...

    , Bulgaria at 35.1 °C (95.2 °F) as well as the capital, Sofia
    Sofia
    Sofia is the capital and largest city of Bulgaria and the 12th largest city in the European Union with a population of 1.27 million people. It is located in western Bulgaria, at the foot of Mount Vitosha and approximately at the centre of the Balkan Peninsula.Prehistoric settlements were excavated...

    , 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. 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
    Musala
    Musala is the highest peak in Bulgaria and the entire Balkan Peninsula, standing at 2,925 m . The summit of the Rila mountain in southwestern Bulgaria, Musala is the highest peak between the Alps and the Caucasus and the highest in Eastern Europe bar the Caucasus.Between 1949–1962 the peak was...

     peak hitting 15.2 °C (59.4 °F) and Elhovo
    Elhovo
    Elhovo is a Bulgarian town in Yambol Province, located on the left bank of Tundzha river, between Strandzha and Sakar mountains. It is the administrative centre of the homonymous Elhovo Municipality...

     hitting 35.6 °C (96.1 °F). On the 15th, Ruse, Bulgaria peaked at 37.2 °C (99 °F). Although it was not a record, this was the highest temperature recorded in the country. Five Bulgarian cities broke records that day: Ahtopol
    Ahtopol
    Ahtopol is a town and seaside resort on the southern Bulgarian Black Sea Coast. It is located on a headland in the southeastern part of Burgas Province and is close to the border with European Turkey...

     hit 28.6 °C (83.5 °F), Dobrich
    Dobrich
    Dobrich is a town in northeastern Bulgaria, the administrative centre of Dobrich Province. With 91,030 inhabitants, as of February 2011, Dobrich is the ninth most populated town in Bulgaria, being the centre of the historical region of Southern Dobruja...

     was 33.8 °C (92.8 °F), Karnobat
    Karnobat
    Karnobat is a town in the Burgas Province, Southeastern Bulgaria. It is the administrative centre of the homonymous Karnobat Municipality. As of December 2009, the town has a population of 18,480 inhabitants.-Geography:...

     hit 34 °C (93.2 °F), Sliven
    Sliven
    Sliven is the eighth-largest city in Bulgaria and the administrative and industrial centre of Sliven Province and municipality. It is a relatively large town with 89,848 inhabitants, as of February 2011....

     hit 35 °C (95 °F) and Elhovo
    Elhovo
    Elhovo is a Bulgarian town in Yambol Province, located on the left bank of Tundzha river, between Strandzha and Sakar mountains. It is the administrative centre of the homonymous Elhovo Municipality...

     recorded 36.1 °C (97 °F).
  • 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 (37.8 °C). Many records were broken, some of which dated back to the 1800s, including Wilmington, Delaware's temperature of 103 °F (39.4 °C) on Wednesday, July 7, which broke the record of 97 °F (36.1 °C) from 1897. Philadelphia and New York eclipsed 100 °F (37.8 °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.
  • 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 °C (95 °F) were reported in many Japanese
    Japan
    Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

     cities, for 33 days in Kyoto
    Kyoto
    is a city in the central part of the island of Honshū, Japan. It has a population close to 1.5 million. Formerly the imperial capital of Japan, it is now the capital of Kyoto Prefecture, as well as a major part of the Osaka-Kobe-Kyoto metropolitan area.-History:...

    , 29 days in Tottori
    Tottori, Tottori
    is the capital city of Tottori Prefecture in the Chūgoku region of Japan.As of 2006, the city has an estimated population of 200,974 and a density of 262.48 persons per km². The total area is 765.66 km²....

     and 25 days in Osaka
    Osaka
    is a city in the Kansai region of Japan's main island of Honshu, a designated city under the Local Autonomy Law, the capital city of Osaka Prefecture and also the biggest part of Keihanshin area, which is represented by three major cities of Japan, Kyoto, Osaka and Kobe...

    . 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
    Kyotanabe, Kyoto
    is a city located in the southern tip of Kyoto, Japan.As of 2008, the city has an estimated population of 65,274. The total area is 42.94 km².The city was founded on April 1, 1997, after the town of Tanabe was reorganized into the city of Kyōtanabe. The Kyō- was added to distinguish it from the...

    , 39.1 °C (102.4 °F) in Gujo, Gifu
    Gujo, Gifu
    is a city in Gifu Prefecture, Japan.As of July 2011, the city has an estimated population of 43,960. The total area is 1,030.79 km².-History:...

    , and higher than 30 °C (86 °F) in 653 cities and 35 °C (95 °F) in 128 cities during September 4 and 5, 2010.
  • The 2011 North American heat wave
    2011 North American heat wave
    The 2011 North American heat wave was a deadly summer 2011 heat wave that affected the Southern Plains, Midwestern United States, Eastern Canada, and much of the Eastern Seaboard had temperatures reaching upwards of on the Heat index/Humidex ratings...

     brought record heat to the Midwestern United States
    Midwestern United States
    The Midwestern United States is one of the four U.S. geographic regions defined by the United States Census Bureau, providing an official definition of the American Midwest....

    , Eastern Canada
    Eastern Canada
    Eastern Canada is generally considered to be the region of Canada east of Manitoba, consisting of the following provinces:* New Brunswick* Newfoundland and Labrador* Nova Scotia* Ontario* Prince Edward Island* Quebec...

    , and much of the Eastern Seaboard
    East Coast of the United States
    The East Coast of the United States, also known as the Eastern Seaboard, refers to the easternmost coastal states in the United States, which touch the Atlantic Ocean and stretch up to Canada. The term includes the U.S...

    .
  • A record-breaking heat wave hit Southwestern Asia in late July and early August 2011, with temperatures in Iraq
    Iraq
    Iraq ; officially the Republic of Iraq is a country in Western Asia spanning most of the northwestern end of the Zagros mountain range, the eastern part of the Syrian Desert and the northern part of the Arabian Desert....

     exceeding 120 °F (48.9 °C), and an "asphalt-melting, earth-parching, brain-scrambling heat of midsummer" in Tbilisi, Georgia. The Iraqis were further challenged by pressure to fast during Ramadan
    Ramadan
    Ramadan is the ninth month of the Islamic calendar, which lasts 29 or 30 days. It is the Islamic month of fasting, in which participating Muslims refrain from eating, drinking, smoking and sex during daylight hours and is intended to teach Muslims about patience, spirituality, humility and...

    , despite heat of 124 °F (51.1 °C) in Bagdad
    Bagdad
    -Places:Australia* Bagdad, TasmaniaMexico* Bagdad, TamaulipasPoland* Bagdad, PolandUnited States* Bagdad, Arizona* Bagdad, California* Bagdad, Butte County, California* Bagdad, Florida* Bagdad, Kentucky* Bagdad, New York* Bagdad, Virginia...

     and 126 °F (52.2 °C) in Diwaniya on 4 August. The extreme heat inspired conspiracy theories
    Conspiracy theory
    A conspiracy theory explains an event as being the result of an alleged plot by a covert group or organization or, more broadly, the idea that important political, social or economic events are the products of secret plots that are largely unknown to the general public.-Usage:The term "conspiracy...

     of the government corruption in Iraq and retaliation from the United States
    United States
    The United States of America is a federal constitutional republic comprising fifty states and a federal district...

     government; and, in Georgia, the Apocalypse
    Apocalypse
    An Apocalypse is a disclosure of something hidden from the majority of mankind in an era dominated by falsehood and misconception, i.e. the veil to be lifted. The Apocalypse of John is the Book of Revelation, the last book of the New Testament...

    , mutant locust
    Locust
    Locusts are the swarming phase of short-horned grasshoppers of the family Acrididae. These are species that can breed rapidly under suitable conditions and subsequently become gregarious and migratory...

    s caused by Chernobyl
    Chernobyl
    Chernobyl or Chornobyl is an abandoned city in northern Ukraine, in Kiev Oblast, near the border with Belarus. The city had been the administrative centre of the Chernobyl Raion since 1932....

    , snake
    Snake
    Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales...

    s imported by unseen enemies, and sun spot
    Sun SPOT
    Sun SPOT is a wireless sensor network mote developed by Sun Microsystems. The device is built upon the IEEE 802.15.4 standard...

    s.
  • Most parts of the United Kingdom
    United Kingdom
    The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

     experienced an Indian summer
    Indian summer
    An Indian summer is a meteorological phenomenon that occurs in the autumn. It refers to a period of considerably above normal temperatures, accompanied by dry and hazy conditions, usually after there has been a killing frost...

     between September and October 2011. The heat wave
    Autumn 2011 United Kingdom heat wave
    The Autumn 2011 United Kingdom heat wave was a period of unseasonably hot weather which arrived towards the end of September 2011 and continued into October. As a result, record high temperatures for the country were broken for the autumn months...

     resulted in a new record high temperature for October at 30°C.

See also

  • Cold wave
    Cold wave
    A cold wave is a weather phenomenon that is distinguished by a cooling of the air. Specifically, as used by the U.S. National Weather Service, a cold wave is a rapid fall in temperature within a 24 hour period requiring substantially increased protection to agriculture, industry, commerce, and...

  • Heat burst
    Heat burst
    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...

  • List of severe weather phenomena
  • Urban heat island
    Urban heat island
    An urban heat island is a metropolitan area which is significantly warmer than its surrounding rural areas. The phenomenon was first investigated and described by Luke Howard in the 1810s, although he was not the one to name the phenomenon. The temperature difference usually is larger at night...

  • The Northern Hemisphere Summer heat wave of 2010

External links