While the Alpine departments are going through their fourth episode of heat wave since May, the summer is already shaping up to be historic from a meteorological point of view. The drought, caused by a lack of rainfall since the beginning of the year, is particularly marked in the Pays de Savoie.
Between historic drought and multiple episodes of heat waves, the Northern Alps are facing an unusual summer. Many sectors of Isère, Savoie and Haute-Savoie have been placed in drought “crisis”, the highest level of alert in this area. The situation is unprecedented, worse than during the 2003 heat wave.
“You have to go back to the summer of 1983 to find such low levels of precipitation”, confirms Denis Roy, director of the Météo France center in Saint-Martin-d’Hères for the Northern Alps. The situation is particularly marked in Savoie where only 15% of the usual precipitation fell for the month of July.
“It is probably the driest month of July for our three departments”, adds the meteorologist. This while july 2022 figure “the second driest month of all months combined” in France since the start of measurements in 1958-1959, according to Météo France. “We have a rainfall deficit of 88 % compared to what would have been necessary”explained on franceinfo the Minister of Ecological Transition Christophe Béchu.
In the Northern Alps, the lack of water has been felt since the beginning of the year. “Only the month of June was able to approach seasonal norms thanks to successive stormy episodes. But we had an extremely dry month of May, like July.”nuance Denis Roy.
A drought against a backdrop of successive heat waves. The Alpine departments have experienced four heat waves since May. And the month of July brings up “a temperature anomaly between 3.5°C and 4.5°C over all three departments” of the Northern Alps, values “very important”notes the meteorologist.
No absolute temperature record has been broken this year, but it could happen on Thursday August 4, which promises to be the hottest day of this new heatwave episode. “Perhaps for the first time this summer 2022, we will exceed the 40°C threshold”he contemplates.
The highest temperatures are expected in Nord-Isère with 37°C announced at the hottest of the day in Bourgoin-Jallieu, or 38°C in Vienne and Roussillon. More broadly, the heat wave should mainly hit the forelands and plain areas, which are more exposed.
If it is still too early to draw up a meteorological assessment of the summer, the month of August does not look any better. The forecast calls for less precipitation and “higher than normal temperatures”. And climate projections raise fears of a repeat of this scenario for the summers to come.
“It may be a taste of what is to come for decades to come with drier summers, more frequent heat waves, earlier and later in the season”concludes Denis Roy.
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