MADISON, Wis. — Smoke from Canadian wildfires has prompted health warnings in the upper Midwest for the second year in a row.
Fires raging in British Columbia and Alberta sent fog across parts of Montana, the Dakotas, Minnesota and Wisconsin on Sunday and continued into Monday morning.
The Minnesota Pollution Control Agency issued its first air quality warning of the season for the entire state on Sunday. The agency said pollution levels will be unhealthy for everyone. The agency urged people to stay indoors and avoid strenuous exercise outdoors until the warning expires at noon on Monday.
The Wisconsin Department of Natural Resources on Sunday issued advisories for several counties in the northern two-thirds of the state, warning that air quality is unhealthy for sensitive people. The advisories would also end at noon on Monday.
At least some smoke could drift south as far as Iowa and Chicago, making skies appear milky late Tuesday or early Wednesday, said Rafal Ogorek, a meteorologist in the National Weather Service’s Chicago office.
According to the Canadian government’s National Wildland Fire Situation report, nearly 90 fires are currently burning in Canada. A fire raging near Fort Nelson in the far northeastern corner of British Columbia has forced evacuations.
Most of the smoke hangs between a mile (1.6 kilometers) and 2 miles (3 kilometers) above the ground, said Ogorek of the National Weather Service. Prevailing winds are driving the smoke south and east, he said.
Canada witnessed a record number of wildfires in 2023 that also caused choking smoke in parts of the US and forced tens of thousands of people to evacuate across British Columbia. Smoke from those fires led to hazy skies and health advisories in several U.S. cities, especially on the East Coast.
An analysis by World Weather Attribution, an initiative that aims to quickly assess the role of climate change in the aftermath of extreme weather events, found that climate change more than doubled the likelihood of hot, dry weather that fueled the fire season.
The chance that more forest fires will break out this summer seems high. Northeastern British Columbia, northwestern Alberta and the southern Northwest Territories are experiencing an intense drought, meaning lightning strikes can start fires that are growing quickly, according to the Canadian National Wildland Fire Situation report.
Loretta Mickley, co-leader of Harvard University’s Atmospheric Chemistry Modeling Group, said her group wrote papers in 2013 and 2015 on the sensitivity of fire activity to different ecosystems with an eye to the future. She said increasing fire activity is consistent with a warming climate.
“What’s going to happen this summer? It depends on what the meteorology looks like today and what happened last winter,” she said. “In some regions, heavy rainfall in winter led to abundant vegetation. If that is followed by drought or drought, then all that vegetation is ready to be burned and become fuel for the fires.”
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Associated Press writers Rick Callahan in Indianapolis, Bob Gillies in Toronto and Steve Karnowski in St. Paul, Minnesota, contributed to this report.
