More than 25,000 residents in three provinces have been evacuated as wildfires remained active and diminished air quality in parts of Canada and the U.S.

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

As dozens of wildfires continue to burn across Canada, flames are sending far-reaching plumes of smoke into the sky and unhealthy air to distant places. Some of the more gigantic blazes have been delivering thick smoke that spread southward into the United States over recent days.