Bad weather: Loire-Atlantique affected by record rainfall – archyworldys

Part of the Nantes ring road and several departmental roads were flooded Sunday morning after the lifting of the red vigilance “Rain-flood” in Loire-Atlantique where the night was marked by rains “Exceptional”, announced the prefecture.

Passed from red to orange then returned to green by Météo France shortly before Sunday noon, the department suffered as expected from significant rainfall. 100 millimeters of precipitation fell on the Loire-Atlantique, Météo-France announced, specifying that 98.3 millimeters have been recorded in the last twenty-four hours in Nantes, the equivalent of 32 days of precipitation, a “Rainfall record”. The previous record, set on February 26, 2020, was “only” 56 millimeters.

The precipitation caused flooding of the Nantes ring road in the interior between the gates of Orvault and Anjou, according to Bison futé, who mentions a “Water stagnation with a height of 30 to 40 centimeters, over a length of 50 meters”.

In many other communes of Loire-Atlantique and neighboring departments, the continuous rains of this Sunday broke the pre-existing record, as evidenced by this map from Météo-France

Cumulated precipitation in twenty-four hours at October 3, 8 hours. Records are circled in black.

At 7:30 a.m., the Loire-Atlantique firefighters had proceeded to “113 interventions related to the rain event”, in particular flooding of premises or falling trees.

“A special intervention was carried out at the Porte du Vignoble on the Nantes ring road at 2 am to secure two people”, said the prefecture on Sunday morning in a press release. “No casualties are to be deplored at this stage. “

“On the departmental road network, departmental roads 39 and 357 are flooded at Saint-Mars-du-Désert and Treillères”, specified the prefecture. In addition, some TGVs that left Paris on Sunday morning for Nantes were diverted by Rennes.

Around 800 homes were still without electricity in Loire-Atlantique at the start of the morning, according to Enedis.

An “atmospheric river” phenomenon amplified by global warming

Precipitation in Loire-Atlantique corresponds to “About a whole month of rain”, according to François Gourand, forecaster at Météo-France, who spoke of “Quantities (…) really exceptional over this period ”. In the North-West, the accumulations often showed around 30 to 60 millimeters with peaks close to 80 millimeters in Morbihan.

According to climatologist Christophe Cassou, co-author of the latest report of the Intergovernmental Panel on Climate Change (IPCC), this extreme precipitation is associated with a phenomenon of “Atmospheric rivers” of which “Global warming tends to increase the frequency” on the Atlantic, he wrote on Twitter.

In #meteo, you may have heard of the Moscow-Paris which brings icy air from Russia to France in… https://t.co/QMIzAhjson

– cassouman40 (@Christophe Cassou)

These rains “Come directly from the Caribbean or more broadly from the western tropical Atlantic”, forming a “An atmospheric river almost continuous from its source (the tropics) to its outlet (France) “. The phenomenon is rare, but not exceptional, according to the climatologist.

In the North-West, a clear improvement is expected in the morning of Sunday. Over the Center-East, the strong winds will continue over the south of the Loire and Rhône departments with gusts of 90 to 110 kilometers per hour, until the beginning of the afternoon.

In the south-east, the Cévennes rains are beginning and “Will strengthen significantly at the end of the morning, taking on a stormy character”, according to Météo-France. “On this episode of the Cévennes Gardoises, Lozère and Ardéchoises, the expected accumulations are of the order of 200 to 250 millimeters, possibly up to 300 millimeters. “

The World with AFP

An “atmospheric river” phenomenon amplified by global warming

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