Smoke from wildfires in Canada has begun drifting across the border into the United States, raising concerns on Friday about possible health hazards in the Upper Midwest, the authorities said.
Warnings about poor air quality were issued in Michigan, Wisconsin and Minnesota along with advisories for people in certain groups to curtail outdoor activity.
In Michigan, meteorologists at the Department of Environment, Great Lakes and Energy said on Friday that the levels of fine particulate in the air would be elevated in the state through Saturday morning.
People in sensitive groups, defined as those with heart or lung disease, older adults, children, pregnant people and outdoor workers, who may be more susceptible to the smoke, were advised to take precautions, such as adjusting outdoor activity.
Particulates are small specks of soot, ash and dust that are picked up by winds and flow hundreds of miles across borders and state lines.
In Canada, wildfire season typically runs from March until October. In Western Canada, fire activity normally sees an uptick in May. The season got off to a grim start earlier this month when two people were killed in the province of Manitoba as a wildfire raged, forcing the evacuation of an entire town.
This week in Saskatchewan and Manitoba, neighboring provinces in Canada’s prairies, dozens of wildfires spread out-of-control, displacing thousands of residents.
A cold front was dragging smoke from the large wildfires in Manitoba and Saskatchewan across the border into Minnesota’s northern region and tribal nations. The smoke was generating a reading of red on the air quality index, a standard measurement used by states to track particulate pollution, meaning it is unhealthy for many members of the general public.
Air quality in the rest of the state was expected to be orange, or unhealthy especially for sensitive groups, Minnesota’s Pollution Control Agency said.
“This will be a long-duration event with multiple rounds of smoke expected,” the agency said. The highest concentration of smoke is expected through Saturday afternoon, before a second round of smoke billows in on Sunday and a third wave arrives on Monday.
In Wisconsin, state officials said hazy skies and elevated levels of fine particle pollution from the wildfires were forecast to drift into the northwestern region of the state before thickening and moving south on Friday.
The advisory in Wisconsin is set to expire at 6 a.m. on Saturday, the Department of Natural Resources said, but there was a chance that the impacts from the smoke could continue in other areas. It said that there was also the possibility that the alert level on the air quality index could reach orange, or unhealthy for sensitive groups, and possibly red, meaning many more would be affected.