More wildfire smoke headed for Minnesota's skies — and could keep coming all summer

An early outbreak of Canadian wildfires will send another wave of smoke over Minnesota from Wednesday night through Thursday, with the potential to reduce air quality, according to a forecaster with the Minnesota Pollution Control Agency.

David Brown, a meteorologist who tracks air quality for the agency, said similar events could unfold all summer long — and people who plan to head outside should keep a close watch on forecasts for cold fronts moving in from the north that could bring more lung-irritating pollution.

MPCA has issued forecasts of summer wildfire smoke for the past two years, since the extreme conditions two years ago. In July 2021, so much pollution wafted over Minnesota's skies that the air in Brainerd and St. Cloud was briefly dangerous for anyone breathing it.

This year's forecast did note above-average risks of fire in Canada, but the early start has been a surprise.

"It's not uncommon to have a little bit of fire activity in the spring before green-up," Brown said, but "these fires are pretty large and extensive for the time of year."

Fire tracking by Natural Resources Canada indicates that dozens of fires are burning out of control from northeast British Columbia through central Alberta and Saskatchewan. The New York Times reported Wednesday that the fires in Alberta had also prompted some oil drillers in that province to cut back on production.

So far, the haze that has descended over the state this week has mostly stayed in the upper atmosphere, according to the National Weather Service. But the cold front moving through on Thursday may mix the particles closer to the ground, where people are more likely to inhale it.

Brown said a line of smoke lingering over North Dakota on Wednesday would slowly move across most of Minnesota, from the Red River to the southeast corner of the state, and will be gone by Thursday night.

An extreme "heat dome" of abnormally high temperatures has helped to dry out parts of Canada where fires are burning right now.

Jesse Berman, an assistant professor at the University of Minnesota's School of Public Health, said it's a challenge to connect single events to climate change, but increased heat, drought and longer fire seasons are all evidence of a warmer planet.

"That's what we've expected under climate change, we're seeing it in other parts of the globe and now we're seeing it here," Berman said.

Some recent studies have tried to make more direct connections between planet-warming pollution and specific fires. One published this week in Environmental Research Letters argues that a third of the fires in the western United States and southwestern Canada can be linked to pollution from fossil fuel companies.

Berman, an environmental epidemiologist, recommended going outside earlier on days when smoke is expected. In the later afternoon, it's more likely that heat and sunshine will add more pollution like ozone into the air, compounding the effect of the haze.

For sensitive groups like children, the elderly, and those with conditions like asthma, the safest option may be to stay inside.

"I have two young kids, and I'll keep an eye out for when we have these types of events," he said.