National heatwave management plan: Information, recommendations and instructions – Health – State actions

What is a heatwave?

The word “heatwave” refers to an episode of high temperatures, day or night, over a prolonged period.

Heatwaves, like extreme cold, pose a danger to everyone’s health.

In France, the period of intense heat which can give rise to heatwaves generally extends from July 15 to August 15, sometimes since the end of June. Very hot days may occur outside of this period. However, before June 15 or after August 15, hot days very rarely deserve the term “heatwave”. The nights are then long enough for the temperature to drop well before dawn.

Since June 2004, Météo-France’s vigilance map has included the risk of heat waves.

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Heatwave management plan

Qualification of heatwave risk

Alerting in the event of risks linked to high temperatures is based on meteorological vigilance, in particular the weather vigilance map updated at 6:00 a.m. and 4:00 p.m., and more frequently if the situation requires it. It is based on the analysis of the two BioMeteorological Indicators (IBM), which are the rolling averages over three consecutive days of minimum (IBM min) and maximum (IBM max) temperatures having been identified as relevant to qualify a heatwave having an impact on health in Seine-Maritime.

The characteristic temperature levels of biometeorological indicators (IBM) of Seine-Maritime are: IBM min : 18°C et IBM max : 33°C.

The probability of simultaneous exceeding of the thresholds by the IBM min and IBM max of Seine-Maritime constitutes the basic criterion for forecasting a heatwave. This information is supplemented by the analysis of more qualitative indicators (intensity and duration of the heat wave, air humidity) and the expertise of Météo-France.

Meteorological vigilance determines 4 levels of vigilance:

Seasonal monitoring – level 1

Is active from June 1 to September 15. Biometeorological (IBM) and health indicators are collected and analyzed daily during the seasonal monitoring period.

Heat warning – level 2

Responds to the change in yellow on the weather alert card. It may be a heat peakof short duration (one or two days). It can also be a persistent heat episodethe IBM are below the departmental thresholds, however the high temperatures persist over time (duration greater than three days).

During heat waves, the ARS takes management measures adapted and appropriate to the characteristics of the episode, in particular the strengthening of information measures and the preparation for an increase in the operational system in order to protect the populations, in particular the most vulnerable.

Heatwave alert – level 3: Heatwave

Responds to the change in orange on the weather alert map; the heat wave is intense and the thresholds of departmental indicators are exceeded for 3 consecutive days and 3 nights. This level is likely to constitute a risk for the entire exposed population. It corresponds to the mobilization of all stakeholders concerned and the implementation of appropriate management measures. It is triggered by the prefectural authority with the support of the ARS. The prefectural authority relies on the ORSEC system depending on local needs.

Maximum mobilization – level 4: Extreme heatwave

Responds to the change in red on the weather alert map. This is a heatwave proven to be exceptional in its duration, its intensity, its geographical extent, with a strong health impact, with the appearance of collateral effects in different sectors. This situation requires the implementation of exceptional measures. As the crisis becomes intersectoral, it requires maximum mobilization and coordination of the State’s response. To do this, the Prime Minister can “entrust the operational management of the crisis to a minister he designates” depending on the nature of the events, the type of crisis or the political direction he intends to give to his action. .

For each of these situations, the prefects will implement management measures adapted and appropriate to the characteristics of the episode (in particular its intensity and duration) to protect the populations, particularly the most vulnerable.

Episode of high heat, find information and recommendations here

The Ministry of Labor recalls the measures that employers must take to protect employees and ensure their safety:

• Ensure employees have a regular and easily accessible supply of fresh drinking water;
• Arrange working hours in order to limit employees’ exposure to the highest temperatures of the day, particularly when the work requires sustained physical effort and/or exposure to very high temperatures (work on roofs, exposure under uncovered hangars). isolated, direct and prolonged exposure to the sun;
• Postpone the most difficult tasks, as long as they are not urgent.

During this period of seasonal vigilance, the labor inspectorate remains mobilized. In addition to the construction sector, other sectors deemed to be at risk are also subject to increased vigilance, such as seasonal outdoor work (agriculture), catering, bakeries, dry cleaners, laundries, but also employees called upon to use their vehicle.

Occupational health services are also mobilized. They remain vigilant regarding the precautionary measures that employers must take towards their employees, particularly those most at risk.

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