Massive wildfires burning out of control in western and central Canada are forcing thousands to flee. The blazes are also beginning to send hazardous smoke toward major cities in the United States.

Blazes in the provinces of Manitoba and Saskatchewan have forced thousands to evacuate. Smoke is expected to waft over the U.S. through the weekend.

Authorities in Manitoba, which shares a border with the U.S., issued a state of emergency. Winds will likely blow wildfire smoke into Midwestern states.