Minnesota and Wisconsin See Air Quality Warnings as Canadian Wildfire Smoke Drifts South

If you’re in the northern part of the Central United States and the skies look smoky, here’s why: Minnesota and parts of Wisconsin were under an air quality alert on Monday morning because of wildfire smoke from Canada.

On Sunday, the Minnesota Pollution Control Agency issued the alert for the entire state, which was set to expire at noon Eastern on Monday. The Wisconsin Department of Natural Resources issued an air quality alert for northwestern Wisconsin that was set to last through 10 a.m. on Monday.

Fine particle levels were expected to reach the red air quality index category, the agency said, which also warned that was “a level considered unhealthy for everyone, across all of Minnesota.” In those areas, officials said, everybody, and particularly sensitive people, should avoid prolonged or heavy exertion and should limit their time outdoors.

The smoke drifted to Minnesota on Sunday, behind a cold front, according to forecasters. In the northern part of the state, air quality had been expected to improve overnight, but smoke was still expected to persist through about midday.

The air quality is unhealthy for everyone.

The smoke in Minnesota and Wisconsin is considered unhealthy for everybody, officials said.

“Air moves long distances and carries pollutants,” the Minnesota Pollution Control Agency said. During air quality alerts caused by wildfires, the air is mixed with harmful smoke. How long wildfire smoke lingers depends on the size of the fires, the wind and the weather.

There are several fires burning in Canada.

Firefighters were battling multiple blazes in Canada over the weekend, including the Teepee Creek fire in Alberta.

One of the biggest, the Parker Lake wildfire, started in Fort Nelson, British Columbia, on Friday and spread quickly with the help of a cold front and winds, according to the British Columbia Wildfire Service.

The Northern Rockies Regional Municipality and Fort Nelson First Nation issued evacuation orders affecting thousands of people in Fort Nelson.

The region has experienced multiple years of drought, making it more susceptible to “extreme fire behavior,” Ben Boghean, a fire behavior specialist for the wildfire service, said in a recorded video update. More winds were expected on Monday morning, Mr. Boghean said, posing challenges to controlling the fire.