The flames never stop spreading. On Saturday July 15, Canadian authorities announced that ten million hectares had burned across the country since the start 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 on Saturday July 15, Yan Boulanger researcher for the Canadian Ministry of Natural Resources.
Worse still, the Canadian government indicated in early July that “this summer could continue to be a very difficult summer for wildfires in some parts of the country” with a “continued potential for higher than normal fire activity” until at the end of the fire season in September.
Cause of these fires since May, a significant 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 be in “water stress”. “This creates unlimited fuel for the flames,” says Cyril Bonnefoy, meteorologist at La Chaîne Météo*. Fortunately, the heat dome currently affecting California does not currently affect Canada. “Even if there are places where it is rather cool, it is summer and it does not rain”, 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.
On site, the flame fronts are sometimes several kilometers wide in spaces filled only with vegetation and forest. “Their first problem is to identify the start of the fire”, notes Éric Florès, head of the departmental fire and rescue service of Hérault who went 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 to ensure that they do not attack installations or do not come too close to human lives”, because these fires are too complex to switch off in view of their location. Difficulties of access coupled with “several hundred fire starts in one day”, against “usually twenty” in May.
Now the fires are spreading across the country: no province is spared. “There are massifs very loaded with plant matter which have never known fires. It burns in areas where there have never been fires”, adds Anthony Collin, researcher at the University of Lorraine and fire specialist.
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 “fuel” – that is, the material to be burned on the ground – is not unlimited. “The flames can go up to 3 km / h, it’s huge. It’s ten times faster than a conventional harvest fire,” deciphers Anthony Collin.
So much so that Canadians quickly found themselves destitute. In early June, Emmanuel Macron announced the dispatch of “a hundred” French firefighters to Canada. Since then, they have taken turns. “Land access is very complex, there can hardly be any ground attack”, observed Éric Florès on the spot. The Canadians therefore attack the “stripes with small portable pumps”, carried in backpacks. “The first town was 250 kilometers from where we were,” also remembers the French firefighter whose mission was to protect an Amerindian community located not far away.
What about the Canadairs? “They don’t make it possible to put out too large fires”, regrets Éric Florès. “On the other hand, they can create sorts of impassable barriers for the flames thanks to preventive water drops”, completes for his part Anthony Collin. But apart from that, “the rescuers are a little helpless, adds the latter. Unfortunately we are disarmed. It goes beyond man.
So what solutions? “The objective remains to prevent the incipient fires from spreading,” says Éric Florès. According to him, Canadian firefighters apply what he calls the “French strategy”. “It consists of massively attacking small fires as soon as they appear”. For megafires that have already grown, “nobody knows how to put that out.” “There is no particular technique.”
To hope to see the lights disappear, there are two possibilities according to researcher Anthony Collin. Either “the flame front arrives in a favorable geographical area” where the fire cannot spread, such as a rocky massif or the sea, or “the weather becomes milder again”. The first hypothesis will only put out a few fires individually, but not the mass that is still ravaging the country.
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 fires on a human scale, details Anthony Collin. There the emergency services will be able to intervene by attacking them on the sides to reduce their intensity”. Until then, the number of hectares burned will undoubtedly increase sharply, the Canadian government recalling on its site that “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.