A majority of forests in Canada face a higher-than-normal wildfire risk this summer, federal scientists say.
The forecast map from Natural Resources Canada suggests every region west of central Quebec will face an above-average hazard.
“We’re starting to see indication of above-normal potential starting in June and carrying on through the summer,” Richard Carr of the Canadian Forest Service said Tuesday.
The risk looks highest in the West. By June, all regions west of Ontario and as far north as the tree line are expected to be at well above the average risk for potential wildfires.
That’s expected to abate somewhat over the course of the summer for the southern prairies. But the hazard will remain elevated for most of the country well into September.
The maps only show risk, Mr. Carr said. “It doesn’t mean we’ll get those fires.”
The forecasts are based on predictions from climate models, which suggest a warmer and drier summer is on its way. Warm, dry and windy weather generally leads to more fires.
“If we have warmer than normal temperatures and less precipitation, then we get dry conditions and might get large and intense fires,” Mr. Carr said.
That’s a big if, said wildfire scientist Mike Flannigan of the University of Alberta.
Predicting weather months in advance, then trying to correlate that with how it might affect conditions in a forest is a difficult game at best, he said.
“Seasonal forecasting you have [to] take with a lot of salt. Not a grain of salt, but a lot of salt.”
He points out that while such forecasts look at general trends, it’s not general trends that cause large, destructive fires. Only three per cent of wildfires in Canada account for 97 per cent of the area burned.
Mr. Carr acknowledges climate models still have trouble predicting crucial patterns such as precipitation.
“Climate modelling has come quite a ways, but it’s still not perfect.”
Still, if the forecast proves prescient, it will fall in line with a long-term trend of increasing wildfire effects.
The average amount of forest burned every year has more than doubled over the past several decades, Mr. Flannigan said. It was about 10,000 square kilometres in the 1960s and is about 31,000 square kilometres today.
Mr. Flannigan puts much of the blame on human-caused climate change.
The fire season is about a month longer than it was in the 1970s. Much of the northern boreal forest is drier and warmer as well.
Research suggests that for every degree of warming, the number of lightning strikes – the cause of about half Canada’s wildfires – goes up by about 12 per cent.
The forecast doesn’t consider the impact of COVID-19 either, Mr. Carr said. Fire bans, restrictions on recreational use and travel in forests may reduce the threat from humans, who account for about half the fire starts in Canada.
“With those restrictions you may see less fire just because there’s less human activity out there.”
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