More than 9 million acres have burned as hundreds of wildfires rage in Canada across, charring an area about 1.5 times the size of Massachusetts.
The blazes have already consumed more than double the amount of land burned in the entire Canadian fire season last year, according to the Canadian Interagency Forest Fire Centre, and it’s only June.
And though the fires are raging in two parts of the country − with an estimated 150 burning in Quebec and nearly that many in British Columbia and Alberta, where fires are more common this time of year − their causes are generally the same.
The majority of Canadian wildfires burning this spring and impacting US air quality are were caused by humans, experts say.
What caused Canadian wildfires?
All fires, whether they’re caused by lightning or people, thrive under conditions that include dry vegetation and hot and windy weather.
Climate change likely played a role in creating the conditions for record breaking heat in May that contributed to the dryness of plants and organic matter, experts say, and the current windiness allows the fires to spread rapidly.
But with the exception of Quebec, which endured lightning storms this spring, most of the fires were caused by human activity, said Mike Flannigan, Research Chair for Predictive Services, Emergency Management and Fire Science at Thompson Rivers University in British Columbia.
That’s not all that unusual.
Human activity, technology and products such as camp fires, power lines, agricultural burning and off-road vehicles typically cause more fires in the early part of fire season, while lightning causes those in the late summer.
Last year, 49% of wildfires across the country were caused by human activity.
In Nova Scotia, that trend leans even more heavily toward human-caused fires.
“Few wildfires in Nova Scotia are caused by lightning and there haven’t been any reports of lightning strikes recently,” said Patricia Jreige, a representative for Nova Scotia’s Department of Natural Resources and Renewables. “So we assume all wild wildfires to to date this season were caused by people in one way or another”
When can we expect the Canadian wildfires to end?
The low-pressure system adrift over Maine and Nova Scotia that has helped funnel the ashen air into the U.S. will probably be “hanging around at least for the next few days,” National Weather Service meteorologist Bryan Ramsey said.
“Since the fires are raging, they’re really large, they’re probably going to continue for weeks,” Ramsey said. “It’s really just going be all about the wind shift.”
The good news, AccuWeather reports, is that parts of the Northeast could see modest air quality improvements though the day Thursday, although it will take until Friday or Friday night for significant improvement in some locations. The bad news is some of the most dense smoke may shift west toward Pittsburgh, Cleveland and Detroit, AccuWeather said.
Flannigan estimates some fires will continue burning for the rest of the summer, as some cover areas as large as 30-by-5 miles making it incredibly challenging for firefighters to completely extinguish. As far as the smoke worsening air quality across the East Coast, he said that will be up to the wind.
Canada wildfire, smoke map
Includes reporting from John Bacon
