Heatwave in early August 2022 in France: assessment

By Gilles MATRICON, meteorologist

This summer of 2022 is marked by many heat waves. That which began on August 1 and ends on Saturday 13 was remarkable for its intensity and duration as well as for its geographical extension to a large part of the territory.

This heat wave is linked to the rise of very hot air from Morocco as well as a blocking anticyclone which rose as far as the British Isles.

In this context, the situation froze for two weeks. Disturbances were thrown back towards eastern Europe or Iceland.

Heat records broken

Due to the presence and persistence of a very hot air mass over France, some heat records were broken, particularly in the southeast and in Brittany.

August 3 was the hottest day of this heat wave with a thermal indicator of 26.47°C.

A critical situation on the fire front

The combination of very high temperatures, low humidity linked to a drying east or north wind and maximum sunshine accentuated the fires and forest fires, as far as Brittany and Vendée. But it is the Landes forest that is paying the heaviest price for this scorching summer with 30,000 hectares of vegetation that have already gone up in smoke since July, which corresponds to 3 times the size of Paris.

Due to the drought, the vegetation suffers. The stress is maximum. The chestnut trees lose their leaves prematurely from this month of August.

Persistent drought and critical hydrological and snow situation

The drought, which began in the spring and has worsened since the beginning of July, is causing many waterways to dry up, such as the Garonne and the Loire.

In the mountains, the melting of glaciers has accelerated since the beginning of August because it no longer freezes, even at high altitude, around 3000 meters.

But when thunderstorms form in the mountains, some of them cause hailstorms that temporarily give the landscape a wintry appearance.

In general, since July 1, total rainfall has been exceptionally low. We are at the record level on 3/4 of the territory.

Heatwave August 2022 / August 2003: a comparable situation?

In both cases, the heat waves of August 2003 and 2022 were preceded by very dry springs linked to the persistence of subtropical high pressures which reached all of western and northern Europe during the summer. However, the heat wave of August 2003 was a notch more intense and above all more lasting and widespread throughout the territory. During the August 2003 heat wave, 75% of the main network’s weather stations recorded monthly heat records. This year, only 5 stations set new monthly records, including Brest on Saturday August 12. And it is especially the west and the south-west of the country which suffered the highest temperatures, the eastern regions having been less affected.

Summer 2022: towards the 2nd hottest summer ever observed in France

Even if the heat wave of August 2022 was a notch below the heat wave of August 2003, this summer 2022 will be in terms of temperatures the 2nd hottest ever observed in France. Despite the drop in temperatures this week, we will remain above seasonal averages due to the mild nights. Finally, after the weekend of August 20 and 21, a new heat wave could be observed in our regions. But this possible heat wave arriving too late, the summer of 2003 should still retain its place as the hottest summer.

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