After experiencing its rainiest month of September in 25 years, France once again suffered an excess of rain of 40% compared to normal in October, Météo-France announced on Thursday.
Over the whole month, which is however far from constituting a record – it does not appear in the list of the 10 rainiest Octobers in France – An average of 132 mm of rain fell across the countrywith precipitation in certain regions representing two to three times the normal amount of rain over the period 1991-2020, Météo-France announced on Thursday.
This is particularly the case in the Var and Nice hinterlands, as well as in the Ardèche Cévennes, which experienced triple the amount of precipitation compared to a normal October.
Repeated floods
An episode of particularly intense rain affected the center-east from October 15 to 18, with six departments (Ardèche, Rhône, Haute-Loire, Loire, Lozère and Alpes-Maritimes) placed on red alert.
It's “never seen before in living memory” emphasized the Minister of Ecological Transition Agnès Pannier-Runacher.
Météo-France confirms that this Cévennes episode is “the most intense ever recorded over two days in the department”.
In Mayres (Ardèche), nearly 700 mm of rain was recorded during the sequence, including almost 500 mm in a single day, indicates the national forecaster.
Between October 24 and 27, another episode of intense rain hit the south of France, particularly the Var and the Alpes-Maritimes.
“During the night from Thursday to Friday, for example, it fell 119 mm in one hour in Vidauban (Var)“which had not “never been recorded” in the department over such a short period, indicates Météo-France.
The rainfall was also twice as high as normal for the month of October at the foot of the Pyrenees and in the Paris Basin, as well as from the South-West to Limousin, from the Center to Picardy, from the south of the Alps to the Mediterranean, in the lands of the Pyrénées-Orientales.
In Paris (149 mm recorded on average) and in Hauts-de-Seine (157 mm on average), October 2024 is the second rainiest month of October behind 1981. In Trappes (Yvelines), the cumulative rainfall reached even an unprecedented value for the month of October, with 169 mm.
Several towns in Seine-et-Marne and Eure-et-Loir were also flooded after the passage of the Kirk depression on October 9, accompanied by significant wind gusts (211 km/h recorded at Iraty in the Pyrenees- Atlantics).
“During this episode, as much rain often fell in one day (October 9) as usually in a month”notably in Noirmoutier (74 mm) or Nogent-le-Rotrou (72 mm), causing rivers to overflow and floods.
1.6°C above normal
Ces exceptional rain – the excess rainfall had already been almost 60% compared to normal in September – are “probably” linked to climate change, even if we will have to wait for studies to formally establish it, Laurent Boissier, climate risk specialist at the insurer Generali, told AFP.
Scientists have already established that global warming, particularly of the oceans, tends to increase the amount of humidity in the atmosphere, contributing to increased precipitation and the extreme nature of certain weather phenomena.
In addition to the rainfall, October was also another month well above seasonal norms in terms of temperatures.
Despite a short cool spell at the start of the month and a deficit of sunshine (-20%), October was on average 1.6°C above 1991-2020 normals, indicates Météo-France.
This “hot anomaly” is particularly marked in terms of minimum temperatures, particularly in the center-east and south-east of the country and follows two abnormally hot months of October.
We have to go back to January 2022 (-0.5°C), more than two and a half years agoto find in France a month considered colder than normal.
Related News :