Heat wave: definition, temperature, dates in France

Il n'y a pas eu de canicule en France durant l'été 2021. Depuis 2015, les canicules ont pourtant augmenté en fréquence et en intensité en France avec une survenue plus précoce (en juin) ou plus tardives (fin août-début septembre) au cours de la période estivale. Des vigilances rouges ont été déclenchées pour la première fois au cours de l'été 2019. Parmi les principales canicules survenues en juin en France, celles de juin 1947, 1976, 2003, 2005, 2006 et plus près de nous 2017 et 2019. Les mois de juin 2005 et 2006 ont connu de véritables canicules avec des températures souvent comprises entre 35 et 40°C, en particulier au sud-est et en vallée du Rhône (plus de 30°C tous les jours à Lyon en 2006). Les personnes âgées sont très vulnérables aux fortes chaleurs et une attention particulière doit leur être portée.

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 big dog.Star that rises and sets with the sun from July 22 to August 22, period characteristic of hot weather.

From how many degrees?

The heat wave is associated with very high temperatures during the day and night for an extended period, usually at least 3 consecutive days.On the meteorological level, it is the exceptional nature of high night temperatures that marks the duration of a heat wave episode.Temperature and duration thresholds are defined and vary according to the departments, explains Météo France.For example: in Toulouse, Météo-France speaks of a heat wave as soon as for 3 days and 3 nights we do not descend below 21 ° C mini and that we exceed 36 ° C Max on the day.

What are the dates of the heat wave plan in 2021?

Each year, the heat wave plan is activated in France on June 1 and until September 15.Its objective is to anticipate the arrival of a heat wave, to define the actions to be implemented at local and national levels to prevent and limit health effects and to best adapt prevention and management measures at the territorial levelby paying particular attention to specific populations

The different levels of activation of the heat wave plan articulate with the 4 colors of Météo France meteorological vigilance:

1. Le niveau 1 - veille saisonnière (vigilance verte)
2. Le niveau 2 - avertissement chaleur (vigilance jaune)
3. Le niveau 3 - alerte canicule (vigilance orange)
4. Le niveau 4 - mobilisation maximale (vigilance rouge)

How to refresh yourself in the event of a heat wave?

In the heat wave, simple gestures make it possible to avoid accidents.We must prepare before the first signs of body suffering.

Sleep well when it's too hot

More than 35 ° C per day, no less than 25 per night, and the temperature of the room which does not want to go down ... sleeping well under these conditions is a challenge.Indeed, the body needs to be in a fresh environment to access rest, and remains on alert when it is not the case: sleep is then lighter, and more frequent awakenings.A few simple gestures, however, improve the situation:

Food, drink and heat wave: good choices

Not too many ice cubes in your lemonade, less salt but no more sorbets...We explain to you how to hydrate yourself when the atmosphere becomes suffocating.

Who are people at risk in the event of hot weather?

The people most at risk in the event of a heat wave are: the people over 65 years old (when one is old, the body transpires little and it has trouble maintaining 37 ° C)).And infants and children under the age of 4 (the body sweats a lot to maintain itself at the right temperature, the child loses water and risks dehydration).Then come: people with strong physical activity, those working in heat (bakery, pressing, construction...) and the homeless.

What are the risks of heat wave?

• Heatstroke

The heat stroke or "hypothermia" corresponds to an overheating of the body: it can no longer deal with the increase in the internal temperature linked to the high temperatures.It mainly affects athletes, but also the elderly, outdoor workers and young children during heat peaks.This also concerns adults who stay for too long in confined and poorly ventilated rooms.For example, staying for hours in a car or in a RER in full heat presents a big risk.The first alert signs that must push to call 15 without waiting are:

While waiting for help: transport the person in a cool place, give them drinking, wet them with fresh water, put humid cloths, lighten their clothes.

• Dehydration

Duffled of sweat by drinking a glass of water, absence of urine for 5 hours or dark urine, drought of the lips...Beware of particularly frequent dehydration in the event of a heat wave.Concretely: a person who transpires and does not drink enough dehydrates.His body lacks water and dehydrates.The elderly are the most exposed.

• Hyponatremia

For the elderly, patients with chronic diseases (kidney failure, heart, hepatic, respiratory, diabetes, cancers...), patients who take certain drugs (diuretics, neuroleptics, antidepressants): hyponatremia (decrease in the concentration of salt in the blood) is an increased risk in the event of hot weather.For people at risk: do not exceed a contribution of 1.5 liters of water in addition to foods rich in water, eating balanced, avoid outdoor outings at the hottest hours and see with the doctor in the event of a depleted salt diet.

• Alcohol and hot weather

Consume alcoholic beverages when it is hot potentially aggravates the effects of alcohol and those of heat on the body.

The best: the prevention of risks linked to the interaction between alcohol and strong heat requires controlled consumption, the ideal being to drink as little alcohol as possible, if not at all.The limit is set at two standard glasses per day for women and three standard glasses per day for men.In the event of occasional consumption, it is better not to exceed four standard glasses at once and do not hesitate to drink water between each glass.People with chronic diseases and pregnant women are invited not to drink alcohol.

• Medicines and heat wave

During heat wave, the body is weakened.Taking medication includes certain risks under these extreme conditions.

Heat wave in France: 2003, temperature record

Several heat waves have touched France in recent years.The last very extensive and intense episodes took place in 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 (567 on the first heat wave, 868 on the second) including 572 in the departments in red vigilance and 10 in the workplace of the victims.The most affected are over 75 but age groups 15-44 and 65-74 were also impacted.

Before, the biggest heat wave dates from August 2003.Its intensity, duration and geographical extent had been exceptional.She had caused 15,000 additional deaths compared to the usual mortality of this period of the year.Other memorable heat waves: that of July 1983 "the longest observed" recalls Météo France, and that of the summer of 1947.

At what period the heat wave in France is?

The heat wave occurs at different periods depending on the country.In France, the hot weather that can lead to a heat wave can start from the end of June and continue until August 15.

Sources:

Coronavirus Sars-Cov-2: management of the epidemic in the event of heat waves.High Public Health Council.May 11, 2020

Heat wave and covid-19: state of knowledge on prevention measures.Public health France.July 23, 2020