A gray haze from wildfire smoke could be seen in Cincinnati, and the entire state of Minnesota is under an air quality alert.

Wildfires in Canada have forced thousands of residents to evacuate in three provinces, impacting air quality in the U.S. — and smoke from the deadly fires has even blown across the Atlantic and reached the U.

The worst wildfires in decades are tearing through Saskatchewan, Canada, and at least two people have been killed in blazes in the neighboring province of Manitoba. Smoke from those fires has triggered air quality warnings in Michigan,