France has issued red flood alerts in three departments as the aftermath of Storm Nils causes widespread chaos. Floodwaters have inundated homes and isolated villages after the Garonne River overflowed its banks, with hydrologists warning that rain is falling on soils that have reached record saturation levels.
Météo France said red flood alerts would remain in place on Wednesday in Gironde, Lot-et-Garonne and Maine-et-Loire, while the number of counties under orange alert would fall from 14 to 12. Monique Barbut, minister for the ecological transition, said a state of emergency would be declared once the floods had ended to fast-track insurance claims.
Lucie Chadourne-Facon, director of Vigicrues, France's flood monitoring service, described the succession of rainy disturbances as 'exceptional', noting that soils are so saturated that as little as 20-30mm of rainfall could trigger floods. 'We are dealing with two parallel phenomena,' she said, explaining that smaller rivers flowing into larger ones cause swelling by propagation, while continued rain reactivates flooding.
Vigicrues reported 'damaging flooding' on the Garonne River downstream from Agen, significant in the Marmande and Gironde regions. Although water levels receded after weekend peaks, they are rising again on the lower Garonne. Officials expect major flooding on Tuesday afternoon on the Maine River, including the city of Angers, and during the night on the Loire River in the Ponts-de-Cé area, with levels rising throughout Wednesday.
The floods follow a series of storms that battered Portugal and Spain, leaving at least 16 dead and forcing thousands to flee. Scientists have not yet conducted attribution studies linking the floods to global heating, but note that warm air can hold more moisture. The EU's scientific advisers have urged Europe to prepare for a world 3C hotter by century's end, while France's national adaptation strategy aims to prepare for 3.2C of global warming.
