Canadian wildfire smoke drifts into U.S., threatening air quality for millions

More than 830 wildfires were burning across Canada on Wednesday, and smoke from the fires was moving south into the United States, where air quality was expected to worsen from the Great Lakes into the Northeast and New England. Winds were carrying smoke from west-central Ontario, northern Minnesota and other fire zones into a broad stretch of the country, threatening visibility as well as breathing conditions for millions.

The heaviest impacts were expected across the upper Midwest, the Great Lakes region, the mid-Atlantic and New England, where forecasts pointed to unhealthy air through the end of the week. The smoke was also expected to dim the sun, turn sunrises and sunsets hazy or vivid, and leave a campfire smell at the surface where it mixed down to ground level. Rain Friday over the upper Midwest and Saturday in the Northeast was expected to help disperse the smoke and improve conditions.

Wildfire smoke is most dangerous for children, older adults, pregnant women, people with heart or lung disease and outdoor workers, who face longer exposure and less control over the air they breathe.

Canada’s federal update put 2026 wildfire activity below the five-year average overall, but fire danger remained elevated in northern Ontario and Quebec. Fire danger was also expected to remain high across the Northwest Territories, Nunavut, northern Manitoba and areas around Hudson Bay, even as some of the largest fires burned in west-central Ontario. Wildfire response in Canada is handled mainly by provinces and territories, with federal support requested when needed.

Natural Resources Canada has tracked fire conditions and occurrences with daily national maps and reports since 1994. Canada’s 2023 wildfire season included more than 230,000 evacuations and over 6,800 wildland fires.