Heavy accumulations of rain are falling this Wednesday, September 4, on several departments around the Mediterranean, including Var and Alpes-Maritimes. Heavy damage could result from this new “Mediterranean episode”, a common weather phenomenon whose intensity is increasing with global warming.
The Old Port is under water. While 12 departments are on orange alert this Wednesday, September 4 for risks of violent storms and heavy rainfall, Marseille has its feet partly in the water. France Bleu Provence, mentions “torrential rains”with “rainfall accumulations of around 50 mm in one hour” have already fallen this Wednesday afternoon on the prefecture of Bouches-du-Rhône. “The Old Port at the bottom of the Canebière is completely flooded,” reports Provence. Result: many roads are closed and traffic is disrupted. The Delta Festival also had to cancel its opening night.
A large part of France, from the South-East to the Centre, is affected by this risk of bad weather between this Wednesday and Thursday. Around the Mediterranean, Météo-France is warning of “episodes of locally intense rain requiring particular vigilance”. Concerning Auvergne and Burgundy, the organization expects “episodes of heavy precipitation causing significant accumulations over large areas, requiring particular vigilance”.
A scenario that leads forecasters to say that a “Mediterranean episode” – characterized by very heavy precipitation over a very short period – is taking place, in particular due to the presence of a cold drop descending from the United Kingdom, which should come into conflict with the warm and humid air of the Mediterranean, explains Météo France.
This air mass conflict would then create “a typical situation” of this meteorological phenomenon which occurs in a privileged way in autumn, from September to mid-December, when the sea is still warm. During this episode, which can occur several times a year, “the equivalent of several months of precipitation falls in just a few hours or days, which can be dangerous and cause serious damage locally,” explains Météo-France.
“This Mediterranean episode is the first of the year,” also advances Adèle Luy, forecaster at Météo France. If the expert affirms Release that this phenomenon is not becoming more common, she notes however that “its intensity increases with climate change and rising temperatures.”
According to the weather institute, heavy precipitation “exceeding 200 mm of water in one day” can be observed, and then cause flooding by runoff and overflow of watercourses, landslides, mud and debris flows. Consequences similar to the Cévennes episodes, specific to the Cévennes sector, and a particular case of the Mediterranean episode.
Update : at 5:31 p.m., with the floods underway in Marseille.
