Thunderstorms, hail, Cévennes episode, wind, record rain and flooding in Lyon: assessment of a very turbulent weekend

News weather

Intense rain, Cévennes episode, hailstorms and violent winds, this weekend was marked by very turbulent weather. First assessment of this event

After the cold at the start of the week, it was the bad weather that made the news this weekend. A very agitated situation linked to a depression which rose from the Bay of Biscay towards the British Isles, bringing in its wake violent thunderstorms on Saturday in the west and intense rain in the east this Sunday.

A very electric and windy Saturday

On Saturday, the disturbance linked to the depression caused strong thunderstorms from Aquitaine to Pays de la Loire, sometimes accompanied by hail. According to METEORAGE services, Saturday, with 3,911 lightning strikes, was the second stormiest day since the beginning of this year, behind April 8.

Ahead of this disturbance, the southerly wind blew violently over the Massif Central and Limousin where monthly wind records were set.

7th Cévennes episode of this year

This start of the year is marked by an exceptional recurrence of Mediterranean and Cévennes episodes, with 7 events of this type: this is a record. In the Cévennes, the southerly flow channeled between the anticyclone over Switzerland and the Atlantic depression has generated and continues to generate a Cévennes episode remarkable for its duration. It started Friday and continues until Wednesday, in bursts. Over the last 48 hours, cumulative rainfall has already reached more than 200 mm, corresponding to more than 1 month of precipitation.

Record rains around Lyon to the Jura this Sunday

The disturbance responsible for the Cévennes episode moved far north, encompassing the Pilat massif, the Lyon region and the Jura. This disturbance has been blocked and has been undulating over these regions since yesterday evening, bringing exceptional amounts of rain. Thus, in Lyon, nearly 100 mm of rain fell over the last 24 hours: this is a daily rain record for the month of April. For comparison, the old record was only 55.9 mm on April 22, 1948. Note that the absolute daily rain record in Lyon is 105.9 mm on May 10, 2021.

Some damage and flooding

This very turbulent situation caused nearly 4,000 power outages in Limousin on Saturday, particularly in Corrèze where the wind blew the strongest. Around Lyon, runoff and flooding were occasionally observed.

Small rivers are experiencing sudden hydrological reactions this Sunday evening, such as the Gier and the Suran.

Conclusion

This month of April knows all the extremes. After the violent storms of April 8, the heat records of the 14th of this month, then the snowfall at low altitude last weekend and several consecutive days of frost, these are the storms which close a month rich in events and remarkable weather phenomena. And the start of May promises to be just as hectic with May 1 marked by strong storms in the east, heavy rains between the Mediterranean and the center of the country and exceptional coolness near the Atlantic.