Minnesota and Wisconsin have issued air quality alerts as some 40 of 146 active Canadian wildfires were declared out of control over the weekend in an ominous start to fire season.
The alerts — issued for the entire state of Minnesota and northwestern Wisconsin — remained in effect Monday morning. Air quality was also being impacted by smoke in Montana and the Dakotas.
Some of the Canadian wildfires have already triggered evacuations.
This past winter was one of Canada's warmest, with little or no snow in many areas, according to Reuters, and the federal government has warned that the country faced another "catastrophic" wildfire season this year.
Last year, smoke from Canadian wildfires spread across the U.S., turning New York City's sky orange and pushing its pollution rating to the worst in the world in early June.
Over the weekend, a fast-growing blaze in British Columbia prompted more than 3,000 residents to flee their homes — but as many as 150 others were courting danger by ignoring an evacuation order, according to reports Sunday.
Northern Rockies Regional Municipality Mayor Rob Fraser said his community was bracing for a "last stand" as high winds were expected to push the flames into Fort Nelson, British Columbia, the Vancouver Sun reported.
About 37 households in town and another 28 in the surrounding rural area were attempting to ride out the Parker Lake wildfire, and Fraser urged them to leave immediately, according to the Sun.
The blaze erupted Friday when high winds blew a tree onto a power line, the Canadian Broadcasting Corp. said.
The wildfire nearly doubled in size on Saturday and covered nearly 9.7 miles (25 square kilometers) on Sunday, with flames no more than 1.9 miles (3 kilometers) from Fort Nelson.
"If we get winds from the west anything like we did on Friday — the day that this fire sparked up — it's going to be extremely difficult to keep it from moving into the community," Fraser said.
Authorities in the Canadian province of Alberta issued an alert about a wildfire nearly 15.5 miles (25 kilometers) southwest of Fort McMurray, but no evacuations were ordered, the Associated Press said.
In 2016, more than 80,000 people had to flee the city in the heart of Canada's oil sands ahead of a wildfire that burned 1,600 homes and other buildings.
