Wildfires raging in Quebec this year have reached a record size. Never have so many hectares gone up in smoke in a single season since at least 1923, the year from which we have reliable data for the commercially exploited forest.
The Society for the Protection of Forests against Fire (SOPFEU) reported on Monday 1.25 million hectares affected by fires in “intensive zone” – south of 51e parallel, approximately — since the beginning of the season. The previous record, dating from 1923, was 1.23 million hectares.
“If we continue to burn at the current rate for the rest of the summer, it will be a year that will come out of all that has been observed in the last century”, warns Victor Danneyrolles, a professor of forest ecology at the University from Quebec to Chicoutimi, which is monitoring the situation closely.
“It’s really a very important threshold that we have crossed,” adds Yan Boulanger, a researcher in forest ecology at Natural Resources Canada. “In the last 25 days, more territory has been burned in Quebec than in the last 20 years combined,” he adds, stunned.
The 1923 record has therefore been surpassed even though fire suppression efforts are much more effective than then. And even if the logging, by rejuvenating the forests, makes them less vulnerable to fires than at that time.
The comparison with the season 100 years ago has its limits, agrees Mr. Danneyrolles. The estimates of the time, less precise than those of today, tended to overestimate the size of the fires. And the intensive area considered was probably a little smaller. But the conclusion is the same: the current season is unprecedented for a century.
In the Nordic area
Throughout Quebec, forest fires experienced their strongest progression of the season in the last week. They are particularly raging in the “northern zone”, north of 51e parallel, where firefighters generally do not fight the flames.
In the northern area, fires driven by strong winds have progressed several tens of kilometers daily. This territory, on the border of the boreal forest and the tundra, has received almost no rain since the end of May. Rare fact, the fires advance there even in the middle of the night.
The main blaze in the northern zone, a complex of fires located south of the La Grande-3 hydroelectric power station, has ravaged more than 700,000 hectares in the last month, making it perhaps the largest fire recorded in Quebec. since the beginning of the registers, underlines Mr. Boulanger.
According to SOPFEU, 1.48 million hectares have burned in the northern zone this year. The total for all of Quebec is therefore 2.73 million hectares. Since the boreal forest of Quebec covers 107 million hectares, 2.6% of it was reduced to ashes this year.
The Canadian Wildland Fire Information System (Natural Resources Canada) indicates that 2.85 million hectares burned this year in Quebec. These data are determined by means of “hot spots” observed by satellite, while those of SOPFEU result from contours traced from a set of aerial surveys.
“The table was set”
Sylvie Gauthier, researcher emeritus at Natural Resources Canada and forest fire specialist, recognizes the exceptional nature of this year’s fires. However, she recalls that “what is happening this year is not absolutely unknown in recent history”.
The detailed registers kept by the government of Quebec since 1923 precisely follow a few terrible seasons. “In Abitibi, from 1916 to 1923, the majority of the years had been extremely dry. The winter was also dry, so there was not enough snow to erase the effect of the drought the year before,” says Ms.me Gautier. The fires had been devastating.
So-called “attribution” climatological studies will reveal the extent to which climate change is contributing to the current fire season in Quebec, says Ms.me Gautier. One thing is certain, such episodes are expected to increase by the end of the century, even in the most optimistic scenario of reducing greenhouse gas emissions.
A study by Natural Resources Canada predicts a fourfold increase in the area burned each year in much of Quebec’s boreal forest. However, this study does not take into account how the forest will change in response to more frequent fires – which could occur on average every 25 years in a given location –, specifies the federal researcher.
“If it burns that often, there’s a negative feedback effect because there’s not enough fuel left,” she says. In 25 years, the trees don’t have time to get very big. In addition, patches of periodically decimated forest may well become more open, slowing the spread of fires.
The current and future evolution of the climate in favor of forest fires is however not in doubt. Since the start of the season, Quebec has experienced weather conditions – temperatures, winds, humidity and precipitation – especially conducive to forest fires, underlines Yan Boulanger.
In May, in a good part of Quebec, the meteorological index used to characterize the risk of forest fires reached peaks, “very far ahead of the previous record”, indicates Mr. Boulanger. “The table was set to ensure that the fire season was exceptional,” he summarizes.