Violent storms in southern France: several departments facing heightened alerts

Storm alerts are in place across southern France today with a major disturbance forecast to cross the bottom half of the country and last well into Friday.

It will bring rainfall of up to 130mm to some areas, as well as hail, lightning, strong winds and intense electrical activity. The barrage comes after an initial salvo of storms in the Pyrénées last night. 

In its morning bulletin, state forecaster Météo France placed three departments on a heightened warning for stormy conditions on Thursday: Ardèche, Drôme, and Isère, with alerts coming into force at 15:00 and lasting until midnight.

In a bulletin later Thursday morning, the forecaster placed orange alerts on two more south-eastern departments, Var and Alpes-Maritimes, and starting from 13:00.

The Météo France update comes after both departments were already placed on heightened storm alert by the unofficial weather warning system of La Chaîne Météo (owned by Le Figaro). 

These warnings ask people to stay indoors where possible, keep up to date with local weather events, and avoid driving on roads that could be impacted by the storm.

Authorities in the Var have advised residents to stay indoors and avoid driving as flooding is expected alongside the heavy downpours. 

Prefecture head Simon Babre told Franceinfo that he was advising residents to "avoid travel" on Thursday, adding that the rainfall could reach as high as 50mm in one hour, and up to 120mm over two to three hours.

He said that the risk of flooding was exacerbated by the recent heatwaves with the exceptionally dry ground less able to absorb water leading to more surface run-off. 

"We are going to be in a period of cumulative risk with these Mediterranean episodes arriving at the end of summer, which require heightened vigilance," said Mr Babre.

The southern half of France currently has tier-two storm warnings in place, asking people to remain vigilant over conditions but with storms expected to be less intense.

For Friday (August 21) the forecaster has placed Corsica on a heightened alert in the morning as the epicentre of storms pass through the area. 

These alerts may change based on the progression of storms, however.

Keeping up with local conditions is therefore paramount. Read our article here for advice on how to do so. 

Barrage of rain and lightning

Stormy conditions will begin early morning on Thursday in the west of the country, quickly moving eastwards by midday where they will increase in intensity. 

The storm pattern will bring periods of brief but extremely intense downpour to the south-east, including the French Riviera and Rhône Valley, Alps, and Corsica, with the Languedoc area also set to see violent periods. 

Downpours bringing 30mm-50mm of rain in an hour are possible, with up to 130mm being forecast across Thursday and Friday. 

Winds of up to 90km/h are possible in the Rhône Valley, as well as hail during the peak of the storm.

There is the possibility of strong electrical activity in mountainous areas such as the Alps and Massif Central.

Beachgoers are being warned of the sudden appearance of the storms when in the water, with waves potentially reaching up to three metres high out at sea. 

Residents should prepare their homes by tying down outdoor furniture and keeping vehicles away from trees that may uproot, as well as ensuring they have an emergency kit in case of a power outage. 

If outside when storms begin, advice differs based on whether you are driving, in the forest, or in mountainous areas – our article here provides an overview.