Why heavy spring rains don’t mean a quiet summer in firefighting

The authorities are preparing to face summer forest and vegetation fires, while around 600 hectares have already burned in the Var at the end of the week.

The fire season has started in France. The Var prefecture announced, Wednesday June 12, that a fire which had burned 600 hectares since the day before in the Vidauban sector had been “fixed”, that is to say contained, but not controlled. The flames did not cause any casualties, but around a hundred people living in nearby hamlets were temporarily evacuated. Monday June 17, the entire department was placed at risk “moderate” by departmental authorities.

The power with which the Vidauban fire spread “surprised everyone”, underlined on franceinfo Lieutenant-Colonel Michel Persoglio. This official assured that agents of the National Forestry Office would carry out “vegetation samples for analyze”because these “do not understand” how the flames could spread so quickly, when rains had recently affected the Var.

France has actually not lacked rainfall in recent months. Spring 2024 was thus the fourth rainiest since records began (in March, April and May), Météo-France announced in taking stock of the season. This is even the wettest spring since 2008. However, these significant precipitations are not synonymous with immunity against violent fires this summer.

“It is difficult to rely on winter or spring rain to tell yourself that we are safe for the summer. Unfortunately, that is not how it works.”

Meteo France

during a press briefing

In the immediate future, the rain made it possible to obtain vegetation “well hydrated”normally quite well immune to possible outbreaks of fire. “Across almost the entire French territory, we have vegetation which has water, which is not dry. If a fire breaks out, [cette végétation] won’t catch fire.” quickly, explains Serge Zaka, climatologist specializing in agriculture, to franceinfo.

How long will the protective effect caused by spring precipitation last? “Even if it stopped raining today for a month, we wouldn’t have a problem.”, anticipates Serge Zaka, who nevertheless issues a warning for all Mediterranean regions. According to him, hydration in these areas is not “not enough to get through the summer” safe from forest fires. “Let’s imagine that it stops raining for two weeks and then a heatwave occurs: the risk of forest fires would increase again”warns the expert.

“Everything will depend on the weather conditions in the coming months”, continues the climatologist, recalling that Météo-France anticipates a hotter than normal summer in 2024. In the Var, the authorities are on alert. “The three-month trend [juin à août] rather favors a warmer and drier outlook than normal for this summerwrote the department prefecture at the end of May. The drought situation therefore remains to be monitored if no rainy episode affects the department in the coming weeks.”

For this summer, the imperative is to be vigilant in France, because everything will depend on the weather for which robust forecasts cannot exceed ten days. Not to mention that due to global warming, linked to human activities, the season conducive to fires is lengthening at the same time as summer extends, eating into spring and shortening autumn.

Drought remains the main risk factor, as “the risk of fire starting is even greaterrecalls the National Forestry Office. When the vegetation is dried out due to lack of rain, a fire becomes possible and can spread quickly.”

It all depends on different elements such as heat, humidity or wind force. This is why the calculation of the level of fire risk, which accompanies the forest weather forecast concocted by Météo-France, is “something very reactive”, says the forecaster. Only two cards per day are produced in this way: one concerns the next day, the other the day after that.

The spring rains allowed the development of“larger and more abundant vegetation than usual”, welcomes Météo-France, which however warns of a potential increase in the risk of fires. This implies “bush fire issues” possibly increased and reinforced in the event of drought.

More vegetation means more “material to burn”Above all “when a drought comes and the plot is not maintained for forest fires”, summarizes Serge Zaka, who points out the risks in the undergrowth and the many areas which should be maintained by man, but are not necessarily.

Everywhere in France, from the Somme to Haute-Savoie, via Gironde and Dordogne, the authorities are calling on residents to clear the land to protect themselves from fires. They underline the effectiveness of this measure, which limits the spread of fires, reduces their power and facilitates the intervention of firefighters. It’s not too late to do it.