The impact of thunderstorms and rain on fires is however difficult to predict since, rather than calming the flames, they could have the opposite effect if they are accompanied by strong winds, or even lightning, the first natural cause of fires. fire, according to Météo-France and firefighters.
Thunderstorms are then expected to hit most of the country on Sunday and end the current heat wave.
France is going through its third summer wave of intense heat, a multiplication that is a direct consequence of the climate crisis, according to scientists, with greenhouse gas emissions increasing in both intensity, duration and frequency.
Three times more hectares burned there than the annual average of the last ten years. The year is also a record in the European Union since records began in 2006.
In Gironde, in the south-west of the country, where the resumption of fire from "Landiras-2" has not progressed for more than 48 hours after ravaging 7,400 hectares of pines, the meteorological service forecasts thunderstorms, accompanied gusts of wind up to 60 km / h on Saturday evening.
A month after two gigantic fires in Landiras and Teste-de-Buch, "the situation changed to favorable" on Saturday on Landiras-2, because the fire "is in the pause phase", according to Lieutenant-Colonel Arnaud Mendousse, spokesperson for the Gironde firefighters.
Further south, in the Landes, the inhabitants evacuated from certain sectors were authorized Friday evening to return to their homes, and the authorities reopened the motorway linking Bordeaux to Spain, closed since Wednesday for a portion of 20 kilometers.
But "the fire is still active on the west side", warned the prefect of Gironde Fabienne Buccio, recalling that a thousand firefighters were still mobilized, supported by European reinforcements (Germans, Romanians, Poles and Austrians).
- "We want to help" -
"We are all volunteers here. We are trained, we want to help," said Tone Neuhalfel, a 36-year-old German firefighter.
In Hostens (Gironde), Romanian Colonel Cristian Buhaiànu assured that his 77 firefighters were "ready to go into the field", soon joined by 21 Polynesian firefighters.
Even the Jura, in the east of the country, with a normally more moderate climate, was hit by two fires, ravaging around 600 hectares of forest.
In Brittany (north-west), it is the mythical forest of Brocéliande, a high place of the legend of King Arthur and the enchanter Merlin, which saw nearly 400 hectares go up in smoke. But the fire was "no longer progressing" on Saturday, according to the prefecture.
In Ardèche (south), a fire having ravaged at least 320 hectares, was "fixed" on Friday while in the neighboring Drôme, a fire which has burned 341 hectares since August 5, was "slowly spreading".
In a growing number of departments, the traditional fireworks of August 15 are prohibited.
Many forest massifs have also been banned from walking this weekend in order to reduce the risk of starting fires.
- Drought -
The precipitation, expected from Saturday evening, will be insufficient to remedy the historic drought that is raging, warned Météo-France. In July, less than one centimeter of rain fell on average.
Storms "will fall on very dry soil, with fairly significant risks of runoff" which do not allow water to be absorbed and increase the risk of flooding "and the risk of hailstones", warned Claire Chanal. , forecaster, during a press briefing on Friday evening.
Over a large part of France, it is forbidden to water and 73 prefects have even banned water withdrawals from farmers in all or part of their departments.