Kirk Depression, repeated flooding in the south and center-west: France recorded 40% excess rainfall compared to normal in October, after having experienced its wettest September in twenty-five years, Météo-France announced on Thursday 31 of October.
During the entire month, which is far from being a record (it does not appear on the list of the ten wettest Octobers in France), an average of 132 millimeters (mm) of rain fell nationwide, with precipitation in some areas. regions that represent two to three times the normal amount of rainfall during the period 1991-2020. This is especially the case in the interior of the Var and Nice, as well as the Ardèche Cévennes, which experienced triple the rainfall compared to a normal October.
An episode of particularly intense rains affected the Center East from October 15 to 18, with six departments (Ardèche, Rhône, Haute-Loire, Loire, Lozère and Alpes-Maritimes) on red alert. Is “Never before seen in living memory” stressed the Minister of Ecological Transition, Agnès Pannier-Runacher. Météo-France confirms that this Cévennes episode is “the most intense ever recorded in two days in the department”. In Mayres (Ardèche), during the sequence, nearly 700 mm of rain were recorded, of which almost 500 mm in a single day, explains the national meteorologist.
Between October 24 and 27, another episode of heavy rain hit southern France, particularly the Var and the Alpes-Maritimes. “On the night from Thursday to Friday, for example, 119 mm fell in one hour in Vidauban (Var)”that there was not “It has never been recorded” in the department in such a short time, explains Météo-France.
Precipitation also doubled normal during the month of October at the foot of the Pyrenees and in the Paris basin, as well as from the southwest to Limousin, from the center to Picardy, from the south of the Alps to the Mediterranean, in the lands of the Eastern Pyrenees. In Paris (149 mm recorded on average) and in the Hauts-de-Seine (157 mm on average), October 2024 is the second wettest October behind 1981. In Trappes (Yvelines), the accumulated rainfall even reached a value without precedents for the month of October, with 169 mm.
Climate change
Several towns in the Seine-et-Marne and Eure-et-Loir were also flooded after the passage of the Kirk depression on October 9, accompanied by significant gusts of wind (211 km/h recorded in Iraty, in the Pyrénées-Atlantiques). ). “During this episode, as much rain often fell in one day (October 9) as normally falls in a month.”particularly in Noirmoutier (74 mm) or Nogent-le-Rotrou (72 mm), which caused river overflows and flooding.
These exceptional rains – the excess rainfall had already been around 60% compared to normal in September. are ” probably “ linked to climate change, although we will have to wait for the studies to formally establish it, declared Laurent Boissier, a specialist in climate risks at the insurer Generali.
Scientists have already established that global warming, particularly that of the oceans, tends to increase humidity in the atmosphere, which contributes to increased precipitation and the extreme nature of certain weather phenomena.
In addition to precipitation, October was also another month well above seasonal norms in terms of temperatures. Despite a brief cold snap at the beginning of the month and a deficit in sunshine (-20%), October was on average 1.6°C above normal between 1991 and 2020, explains Météo-France.
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Record
This “hot anomaly” It is particularly marked in terms of minimum temperatures, especially in the central-east and southeast of the country, and follows two abnormally hot October months. You have to go back to January 2022 (-0.5°C), more than two and a half years ago, to find in France a month considered colder than normal.
