‘Stay home’: Red alerts for flash-floods raised in southern France

Red weather alerts have been raised in southern France as storms continue to batter the Mediterranean coast and southern Massif Central today, creating a high risk of flash flooding. 

People in the area are asked to limit their trips and stay inside.

These warnings, the highest possible, cover the Gard and Hérault departments with up to 400mm of rain set to fall in the Cévennes and nearby valleys today.

However, the intensity of the storms also threatens more urban areas in the departments along the plains near the coast. It is unusual for these storms to also affect the plains and coastal areas with such intense rainfall. 

Forecasters have also highlighted the risk of ‘stationary storms’, with rain clouds staying in one location for several hours and dropping continuous rainfall over the area. This could impact urban centres as well as rural locations, depending on where the clouds stop.

Up to 80mm could fall in an hour in both the plains and valleys, leading to flooding both from the intensity of the rain and quickly rising river levels. 

Schools have been closed and public transport services cancelled. 

The Hérault prefecture is urging people to cancel all non-urgent outdoor activities and to stay inside. The ground is particularly dry and hard from months of drought meaning it is harder for water to be absorbed resulting in flash flooding.

“This is the first such event we've had after four to five months of drought and heatwaves, so vigilance is crucial,” said prefect Chantal Mauchet to media outlet Ici. 

Drivers should avoid all non-urgent journeys and be careful if out as roads can quickly flood, including bridges. 

The alerts, implemented this morning, will stay in place until midnight according to the current forecasts by state forecaster Météo France. 

The nearby Ardèche, Lozère, and Bouches-du-Rhône departments are also facing tier-three orange alerts, the second-highest possible, for heavy rain / flash flooding. 

Four of the five departments are also on a tier-three alert for storm conditions (with Bouches-du-Rhône on a tier-two yellow warning), and much of the north and centre of the country is on a tier-two alert for storms, with several storm formations potentially hitting as far north as the English Channel.

You can read about how to keep up with live alerts in our article here, and check live warnings through the Météo France website. 

You can read more about what to do in light of red and orange storm and rain warnings in our article here.

‘We are expecting significant water level rises’

The intense weather system, known as an épisode cévenol, comes after storms hit the south of France yesterday evening, and is the first such event of the upcoming autumn/winter season.

These storms see humid, warm air cloud systems from the Mediterranean blocked from moving inland by the mountains and clashing with the cold mountainous air, leading them to deposit much of their rain in the Cévennes.

This rain falls in a short amount of time, increasing the risk of flooding.

They are a subset of a wider storm pattern known as épisodes méditerranéens, which can bring similar conditions to several departments across the south of France that border the coastline and mountainous inland areas.

Intense rain began falling at around 03:00 this morning in the affected departments.

Up to 200mm of rain is set to fall at lower altitude levels in the departments, rising to between 300mm and 400mm in valleys near the Cévennes range. 

Several rivers in the area have been put on a heightened risk of flooding – you can follow live updates through the official VigiCrues flooding website. 

“Rainfall has been intensifying over the past few hours in the Cévennes area, specifically around Anduze, Alès, and Bessèges. Three of our waterways have been placed under orange alert for the day. We are expecting significant water level rises," VigiCrues forecaster Antoine Dussuchale told media outlet Ici. 

“Météo France forecasts a shift in the rainfall later in the day, moving towards the foothills and the plains of the Gard and Hérault departments,” he added.

“This could particularly affect the Vidourle river basin and even the Nîmes metropolitan area. There is a forecast of severe thunderstorms, with the potential for storms to stall over an area and produce heavy rainfall totals.”