Srebrenica

The heat wave is one period of very strong heat during the be.

Even if there does not exist official definition, it is considered that there is heat wave when, in a given sector, the temperature remains high and the thermal Amplitude low. I.e. the temperature does not go down in lower part from 20°C the night, and reached or 45°C exceeds the day, this more especially as the phenomenon lasts several days, and a fortiori several weeks, heat accumulating more quickly than it is not evacuated by Convection or Rayonnement.

This definition would be applicable in France or Western Europe. Indeed, the concept of heat wave seems relative and the heat wave in Africa or Scandinavia could be based on other values. It is probably this difficulty which prevented the creation of a universal definition.

In Occident, the heat wave was supposed to occur at the time when Sirius, the the most brilliant star of the constellation of the Large Dog, rises and lie down at the same time as the Sun, i.e. roughly speaking , with the Moyen-âge and nowadays, during August.

Etymology

Heat wave comes from the Latin Canicula , which means “small bitch”, the other name of the star Sirius. It thus concerns in the beginning only the annual period from July 24th to August 24th, where this star lies down and rises at the same time as the Sun.

History

Three millenia ago, Sirius rose with the Sun at the beginning of July. One allotted bad influences then to him (diseases caused by heat and howls of the dogs).

In the ancient Rome, one tried to entreat the harmful influence of Sirius on the harvest S by immolant russet-red bitches (color of the star at the time).

A long time, the canicular summers took place several years of continuation. They often went by group of three as in 1383 - 1385, by group of four as in 1331 - 1334 and 1778 - 1781, by group of seven as in 1757 - 1763… and even by group of twenty as in 1718 - 1737!

Medical consequences

Strong heats, associated with the atmospheric high pressures, can last long Semaine S and sometimes of the Mois. In the countries in the process of development, it cause a shortage of Drinking water and quality of this water lowers it, which implies many deaths indirectly.

The non-drinking water consumption was in the past a major cause of mortality. Thus, in France, there was 500 000 died in 1636, 700 000 in 1718 as in 1719. It was the same at the time of the heat wave of 1666 in England.

The be canicular of 2003 involved a on-mortality of 15.000 people in France (20 000 in Italy) during the first 20 days of August, that is to say an increase in mortality of more than 40%. The unpreparedness of the country and the disorganization of August transformed this exceptional climatic event into medical catastrophe majeure.
For the same period, Italy saw its mortality growing of 8.000 people, the truth known in 2005 denounced a underestimated assessment with 20.000 deaths.

Economic consequences and environmental

The heat waves can cause Sécheresse S catastrophic. The large fire of London in 1666, which devastated the city in a few hours, was supported by the lack of water available to stop the flames.

Electric overconsumption due to the intensive use of the air-conditioners and the weak hydroelectric production involves moreover one brutal imbalance of supply and.

Whereas the average costs of the mégawattheure (20 minutes of production of a nuclear plant of 1 GW) for section 11-12 hours with European Stock Exchange EEX were of 73 euros during the first six-month period 2006, it was negotiated on July 25th with the historical records of 2000 euros after the withdrawal of Poland and Tchéquie.

In France, the State then regularly compensates the economic actors who suffer injuries because of the too high temperatures by issuing the situation of " catastrophe naturelle".

The periods of heat waves generally correspond to exceptional years for the wine production, the vine well indeed supports very strong heats thanks to its very major rooting. Still it is necessary that the wine grower can work his wine.

To protect itself from the effects of the heat wave

Protection of the individual

The state of heat wave being defined like an extraordinary event, the populations are not often accustomed to managing these events (contrary to “usual” heats). Mainly two risks are counted:

the Heat stroke: if, under the effect of the environment, the body temperature rises beyond 40,5 °C, the operation of the cell S is faded;
the Dehydration.

Five categories of people are particularly exposed:

young children: they are not independent, and if he claim spontaneously with drinking, while crying, it are not able to drink without assistance nor to protect itself from heat;
people making of the physical efforts, because of the Thermogenesis of muscular work: workers exposed to extreme heats (for example working of the buildings), sportsmen, hikers;
people having cardiac diseases: the Perspiration or the excessive hydration will modify the blood Pression and its composition;
elderly: those lose the concept of thirst and must thus drink even if they do not want of it;
the Sans-abri S, which cannot be protected from heat and are in general excluded from the fresh places (hall of air-conditioned supermarket and cinema).

The precautions to be taken are

to protect itself from the sun; in particular, never not to leave a child alone in a car or a caravan, even for a short duration;
to refresh itself by wetting the skin (brumisation, baths, showers) and by using a Ventilator, even while going in air-conditioned places,
of drinking sufficiently (and before having the intense feeling of thirst), according to the physical-activity and heat.

The case of the elderly is delicate because those frequently have a arterial Hypertension (HTA) or a Cardiac failure, whose treatment utilizes Diurétique S and/or a mode without salt. The absorption of water without salt can lead to a Hyponatrémie (content of Sodium in the Sang drops). Certain doctors consider that the risk of dehydration and hyponatremy takes precedence over the risk of edema: swelling of the members and pulmonary edema; indeed, the pulmonary edema is easy to detect and treat (including by a general doctor in residence), whereas dehydration and the hyponatremy are difficult to detect and more mortals. Some thus recommend the suspension of modes without salt and diuretic; but this does not make consensus, and in all the cases, the decision will be caught in agreement with the attending physician, only qualified on the matter.

Protection of the dwelling

See also: Air-conditioner, environmental High-quality

August 1st

Seek

According to a study of 2007 realized by ECA and CNRS, a deficit of rain in Europe of the South (Italy, south of France and Spain) in winter would be heralding heat wave with 70% on the Central Europe and north|date= October 14th, 2007 .

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