(NEW YORK) -- Over 800 wildfires are burning through forests in Canada, creating heavy smoke that could potentially affect millions of Americans this week.

Some of the largest blazes are in west-central Ontario province. Those fires are burning through thick forests, releasing significant amounts of smoke.

Ontario has been experiencing a heat wave, with record-breaking temperatures soaring over 100 degrees Fahrenheit, according to forecasts.

There are also at least a dozen wildfires burning in northern Minnesota near the Canadian border.

The wind will begin directing that very heavy smoke into the U.S. Tuesday night, creating dangerous air quality for millions across the upper Midwest and Northeast Wednesday.

By sunset on Wednesday, very heavy smoke may reach New York City and Providence, Rhode Island. It will stream through Green Bay, Milwaukee, Grand Rapids, Detroit and Buffalo before then.

Conditions in New York are not expected to be as intense as they were in June 2023. Hazy skies are expected and air quality will likely become unhealthy.

Copyright © 2026, ABC Audio. All rights reserved.