Weather alerts raised as violent storms forecast to sweep France

Eight French departments are on (high) alert and 50 on (yellow) alert as violent storms are forecast to sweep the country during the night of August 31 - September 1, with south and central areas expected to be most affected. 

The departments on high alert for August 31 are all in south and central France, namely: Allier, Ardèche, Côte-d’Or, Gard, Lozère, Nièvre, Puy-de-Dôme and Saône-et-Loire. 

Ardèche and Gard are also on alert due to the possibility of local flooding, as the storm may bring intense rain.

“An active disturbance is moving into south-eastern regions on Sunday afternoon. In the evening, an ‘épisode Méditerranéen’ will set in with very heavy storm precipitation,” said state forecaster Météo-France in its daily bulletin.

“These may exceed 80mm in less than three hours, with totals of over 100mm expected over the course of the episode, and up to 150mm locally.

“Thunderstorms will also bring strong electrical activity, hail and locally strong wind gusts.”

An épisode Méditerranéen (sometimes called an épisode cévenol when it is predominantly the Cévennes of Gard, Ardèche and Hérault) is caused by a clash of warm from the Mediterranean sea clashing with cold air in the mountain ranges of the Massif Central or Alps. 

This sudden interaction leads to intense downpours where weeks worth of rain can fall in a few hours. 

For the Auvergne region, forecasters expect a short albeit violent episode on Sunday evening. 

Rainfall could reach 15 to 30mm in under an hour, with six-hour totals of up to 40mm. 

Winds could peak at 80 to 100km/h, locally higher, and hailstones could reach medium to large size.

Residents in areas on high alert are advised to limit travel where possible, avoid walking or driving on flooded roads, and secure outdoor objects that could be blown away. 

Authorities also recommend checking local updates regularly as the situation can change quickly.

Bad weather to continue on Monday

Six departments are expected to remain on high alert on Monday, September 1: Ardèche, Bouches-du-Rhône, Drôme, Gard, Lozère and Vaucluse. 

Rain and flooding risks will also apply to five of them: the Ardèche, Bouches-du-Rhône, Drôme, Gard and Vaucluse.

Météo-France says more areas may be added on Monday, particularly for neighbouring departments further east.

The orange level indicates a significant risk of dangerous weather phenomena, with advice to the public to be prepared and follow safety recommendations.