In the two southern departments, «the stationary thunderstorms are well established» and «the exceptional intensity of the precipitation observed requires a passage in red vigilance», announces the meteorological service.
«There are currently values of more than 150 mm in the south-east of Hérault and the Sommières region», specifies Météo-France in its 4:15 p.m. bulletin.
«Currently the episode concerns the Montpellier region. In the hours to come, an additional 100 mm may fall, bringing the total rainfall over the episode to maximum values between 200 mm and 250 mm», adds the national weather service. .
The end of this episode of stationary thunderstorms, «the first of the season» notes Météo-France, «is expected around 10 p.m.». «Other rain accumulations may be added but the strongest should therefore have passed.»
Red vigilance for thunderstorms is activated in the event of «very violent thunderstorms, likely to locally cause very significant damage», in particular «on dwellings, parks, crops and plantations».
The populations are then invited to stay at home, in a permanent building, and not to use their vehicle.
In addition, thunderstorms were developing Tuesday afternoon from the Massif Central. They should go up «rapidly (…) towards the north of Rhône-Alpes, Burgundy and Franche-Comté and to the German borders».
«These storms will generally be quite brief but sometimes violent with sustained gusts of wind (around 100 km / h), hail and very high precipitation intensities locally giving fairly large accumulations», announced Météo-France, justifying the placement of 25 departments of these regions in orange vigilance.
«The improvement will come quickly behind this new stormy wave and become more widespread overnight.»