2023-07-19 15:08:18
DECRYPTION – Canada is facing megafires on an unprecedented scale, the first having occurred in early May. Ten million hectares have gone up in smoke in the country since the beginning of the year.
The flames never stop spreading. Saturday, July 15, Canadian authorities announced that ten million hectares had burned across the country since the beginning of the year. This represents the equivalent of the area of Portugal. A sad record, the precedent dating from 1989 with 7.3 million hectares gone up in smoke, according to national figures from the Canadian Interagency Forest Fire Center (CIFFC).
Two firefighters died fighting these megafires, the first of which appeared early in early May. Monday July 18, 882 fires were still active in the country, including 579 considered out of control. For the time being, the fires are mainly concentrated in the boreal forest, far from inhabited areas. “We find ourselves this year with figures that are worse than our most pessimistic scenarios“, explained to AFP Saturday, July 15, Yan Boulanger researcher for the Canadian Ministry of Natural Resources.
Worse still, the Canadian government indicated at the beginning of July what “this summer could continue to be a very difficult summer for wildfires in parts of the country” with a “a continued potential for above normal fire activity» until the end of the fire season in September.
Expanses of forest
Cause of these fires since May, a major state of drought in a large part of the country due to rainfall well below seasonal averages, for months. This favors the resumption of fires in a country where the majority of fires are of natural origin, mainly because of lightning strikes.
The vegetation therefore lacks water: it is said to bewater stress». «This creates unlimited fuel for the flames», emphasizes Cyril Bonnefoy, meteorologist at The Weather Channel*. Fortunately, the heat dome currently affecting California does not currently affect Canada. “Even if there are places where it’s rather cool, it’s summer and it’s not raining», nevertheless points out the meteorologist. According to him, this heat dome could move up over British Columbia – in western Canada – by the end of July.
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On site, the flame fronts are sometimes several kilometers wide in spaces filled only with vegetation and forest. “Their first problem is‘identify the start of the firesays Éric Florès, head of the Hérault departmental fire and rescue service, who traveled to Quebec for three weeks in June to support his Canadian counterparts.
He explains that Canadian firefighters can sometimes let the flames spread by “keeping them under surveillance by checking that they do not attack the installations or do not come too close to human lives”, because these fires are too complex to extinguish given their location. Difficulties of access coupled withseveral hundred fire starts in one day», against a “twenties usually” in May.
From now on, the fires extend to the whole country: no province is spared. “There are beds heavily loaded with plant matter that have never experienced fires. It burns in areas where there have never been fires,” adds Anthony Collin, researcher at the University of Lorraine and fire specialist.
A fire that feeds itself
One of the main difficulties lies in the operation of such lights. Concretely, the flames of the huge fires create plumes of smoke and heat effects. This heat meets colder air present on the ground, pushing the air mass towards the atmosphere. An internal depression then occurs, causing gusts of wind. These themselves fan the spread of the flames. The fire is therefore self-sustaining without the firefighters being able to do anything about it. Only the “combustible– that is, the material to be burned on the ground – is not unlimited. “The flames can go up‘To 3 km/h is huge. It’s ten times faster than‘a classic harvest fire», deciphers Anthony Collin.
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So much so that Canadians quickly found themselves destitute. In early June, Emmanuel Macron announced the sending of a “hundred” of French firefighters in Canada. Since then, they have taken turns. «L’ground access is very complex, there can hardly be any attack on the ground”, observed Éric Florès on the spot. The Canadians are therefore attacking the “stripes with small portable pumps”carried in backpacks. “The first city was 250 kilometers from where we were”also remembers the French firefighter whose mission was to protect a Native American community located nearby.
And the Canadairs? “They do not extinguish large fires», regrets Eric Flores. “On the other hand, they can create sorts of impassable barriers for the flames thanks to drops of‘preventive water», complete for his part Anthony Collin. But other than that,the emergency services are a little helplessadds the latter. Unfortunately we are disarmed. It goes beyond man».
Unstoppable fires?
So what solutions? “The objective remains‘prevent incipient fires from spreading», says Éric Flores. According to him, Canadian firefighters apply what he calls the “French strategy». «This consists of massively attacking small fires as soon as they appear.». For megafires that have already grown in size, “no one knows how to turn it off». «He does‘there is no special technique.»
To hope to see the lights disappear, there are two possibilities according to researcher Anthony Collin. Either “the front of flames arrives in a favorable geographical area” where the fire will not be able to spread, such as a rock mass or the sea, either “the weather is getting nicer again”. The first hypothesis will only put out a few fires individually, but not the mass that is still ravaging the country.
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Salvation could therefore well come from the weather conditions and especially from the rain. According to the specialists interviewed, it could return around September or October, just like the snow thereafter. “The rain will make it possible to iron out human-sized fires, details Anthony Collin. There the emergency services can intervene by attacking them on the sides to reduce their intensity.. By then, the number of hectares burned will undoubtedly increase sharply, the Canadian government recalling on his site what “Canada has the third largest forest area in the world” with “nearly 362 million hectares».
It therefore remains difficult for the time being to imagine a total extinction, as the forests are vast and the fires powerful. However, one fear remains. “There have already been droughts that persisted in the fall, especially on the west coast of Canada”, recalls meteorologist Cyril Bonnefoy. News that would be catastrophic for firefighters already exhausted by these bitter fights against the flames.
*The Weather Channel is a property of the Figaro group.
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