Here's where wildfire smoke is spreading in Canada and the U.S.

As wildfires continue to rage in Western Canada, communities in affected areas and surrounding provinces have been blanketed by thick plumes of smoke, prompting air quality alerts extending into parts of the United States this week.

Smoke conditions in some parts of the U.S. Midwest have become so bad that the air quality has been categorized as "hazardous."

Exposure to wildfire smoke has been found to cause early death and respiratory issues, says a 2024 report from Health Canada.

Air quality warnings have been issued by Environment and Climate Change Canada throughout Manitoba, Saskatchewan, Alberta and Ontario. Fifty-three communities in southeastern Manitoba, for example, have received alerts about wildfire smoke causing poor air quality and reduced visibility.

The warnings stated that conditions in some Manitoba regions are improving as the smoke drifts eastward and away from the affected communities, but it is expected to linger in areas like Flin Flon and Cross Lake, where local wildfires are still evading control.

Communities in northern Saskatchewan, such as La Ronge, have also been under air quality warnings for the past several days. La Ronge, Air Ronge, the Lac La Ronge reserve and other communities within a 20-kilometre radius have now been ordered to evacuate. 

A number of special air quality statements were also issued for more than a dozen communities in northwestern Ontario early Monday morning. The statements warned that wildfire smoke was expected to remain in the area for the next several days.  

Over the weekend, smoke drifted toward the Upper Midwest in the U.S., impacting northwestern Wisconsin, eastern Nebraska, northeastern North Dakota and most of Minnesota.

A statewide air quality alert has been issued for Minnesota until Wednesday by the Minnesota Pollution Control Agency. The alert states that the smoke will likely reach northwest and north-central Minnesota by Monday evening, following behind a cold front that's moving southeast.

The Air Quality Index values used in the U.S. are expected to reach the "hazardous" category in northwestern Minnesota. At that level, the public is advised to avoid physical activity outdoors, and high-risk groups — including those with lung and heart disease, seniors and young children — should remain indoors.

The alert warns residents in northwestern Minnesota that they can also expect mild ashfall and reduced visibility. 

The smoke is expected to drift southeast in the coming days, according to BlueSky Canada's smoke forecast, which combines Alberta and British Columbia's forest fire data with weather forecast models to predict smoke concentrations. 

Air Quality Health Index (AQHI) values — the scale used in Canada to relate air quality to health — were at seven in Flin Flon on Monday evening, putting it in the "moderate" health risk category.

An air quality warning for Flin Flon issued on Monday morning stated: "During heavy smoke conditions, everyone's health is at risk regardless of their age or health status."