Canadian wildfire smoke is triggering air quality alerts across the U.S. Midwest and Northeast on Thursday, as the northern nation’s boreal forests continue to burn at a rate not seen except for a historic season in 2023.

Smoke traveling from wildfires in Canada, North Dakota and Minnesota triggered an air quality warning in northern Wisconsin.

An air quality advisory has been issued for the northern half of Wisconsin as Canadian wildfire smoke has mixed down the the surface.