Under the effect of climate change, the hot weather starts earlier and earlier, from mid-June. When do we talk about heat wave? From what temperatures?
The heat wave episodes could be more frequent in France in the coming years because of global warming. According to Météo France, temperatures should increase by +2.7 ° C by 2050 and +4 ° C by 2100. Heat waves could occur from early June and last until mid-September. In a +4 ° C France, they could appear from mid-May and extend until the end of September.
What is the definition of the heat wave?
The word “heat wave” comes from the Latin “canicula” which means “little female dog”. Canicula is the name given to the star Sirius (which comes from the Greek “seirius”, meaning “burning”, “ardent”). which is in the constellation of the large dog. Star that rises and sets with the sun from July 22 to August 22, a period characteristic of hot weather. The heat wave designates an episode of high temperatures during the day as at night for an extended period, usually at least 3 consecutive days. It can constitute a health risk for fragile or overexposed people.
What are the recommendations in the event of a heat wave?
- Drink water and stay in the fridge
- Avoid alcohol
- Eat sufficient
- Close the shutters and windows during the day, ventilate the night.
- Wet the body (lukewarm but not cold shower)
- Give and take news from his loved ones.
What are the dangers of the body for the body?
Prolonged heat exposure is significant stress for the body. The human body tries to adapt to it. It sweats more and the blood vessels expand. If it cannot maintain its temperature around 37 ° C when it is very hot or if fluids or body salts are not adequately replaced, several problems can occur:
Holds can also worsen pre -existing diseases, be responsible for heat -associated diseases. Taking certain drugs can worsen heat -related effects, especially in risky people.
► cramps, nausea, inexplicable state of fatigue, important headache, incoherent comments or high fever: call 15
Temperatures, levels of vigilance: What are the criteria for swinging in a heat wave?
On the meteorological level, it is the exceptional nature of high night temperatures that marks the duration of an episode of heat wave. Temperature and duration thresholds are defined by Météo France and vary according to the departments. There are three levels of vigilance in case of hot weather:
► The level of yellow vigilance corresponds to:
- A heat peak: short -term exposure (1 or 2 days) to intense heat
- or a persistent episode of heat but which remains under the alert thresholds
► The orange vigilance level corresponds to a heat wave: intense heat period for which the averages over 3 consecutive days of night and day temperatures reach or exceed the departmental thresholds, and which is likely to constitute a health risk in particular for fragile or overexposed persons.
► The level of red vigilance corresponds to an extreme heat wave: exceptional heat wave by its duration, its intensity, its geographic extension, with a high health impact for any type of population, and which can lead to the appearance of collateral effects, especially in terms of activity continuity.
Heat waves in France
We listed 50 episodes of heat in France since 1947. Over the past 35 years, they have been 3 times more numerous than over the previous 35 years. The number of days of heat waves has been multiplied by 9: “The frequency and intensity of heat waves are led to increase in the coming decades. The frequency of events should double by 2050.” Today, THE heat waves have uoccurred earlier (in June) or later (end of August-early September). Among the main heat waves in Francethose of June 19471976, 20032005, 2006.
► Summer 2023: The last heat wave was recorded in August 2023 with temperatures exceeding 40 degrees in several regions of France. Departments have been placed in red vigilance, proof of an extreme heat wave.
► Summer 2022: The heat wave episode began on June 15, 2022. This episode was unprecedented by its precocity and its intensity. Several temperature records for a month of June and also in absolute terms have been recorded. A second scorching episode touched France between July 12 and 20 and a third between July 31 on August 14.
► Summer 2019: between June 24 and July 7 and July 21 and 27. According to the bulletin published by Public Health France in September, 1435 deaths were observed during this heat wave. The most affected are over 75.
► June 2005 and 2006 with temperatures often between 35 and 40 ° C, in particular in the Southeast and in the Rhône valley (more than 30 ° C every day in Lyon in 2006).
► August 2003. Its intensity, duration and geographic extent had been exceptional. She had caused 15,000 additional deaths compared to the usual mortality of this period of the year in France.
► Other memorable heat waves: that of July 1983 “The longest observed” Recalls Météo France, and those of the summer of 1947 and 1976.
