Extreme wind gusts assessment in France

Extreme wind phenomena generated during convective events are reported every year in France and cause significant material losses. In 2022, several significant events were observed, for example in Normandy in June where a kite surfer lost his life or in August in Corsica where a new wind gust record was recorded (225km/h). However, convective wind gusts are not considered in the design process of residential and industrial infrastructures. Therefore, our study assesses the available databases on convective wind speeds monitored or estimated by MeteoFrance and Keraunos for the period 2000-2019 in order to define a methodology to estimate the wind gusts return level.

Since all these convective events occur during a thunderstorm, the originality of this work was to use lightning data to separate convective from non-convective events. In addition, we considered all available data by projecting them onto the same grid (Meteorage lightning grid with 25 km resolution). A first probability analysis and conditional probabilities knowing the occurrence of a thunderstorm were deduced over the period and by seasons.

Then, we will focus on a very convective region (North-East of France) to evaluate the possibility to estimate the return level of wind gusts with the designed available dataset.