The smoke from the Canadian wildfires drifting across the eastern US|NOAA

Heavy winds are blowing dangerous smoke from over 100 wildfires burning in Canada into the US Midwest and Northeast, forcing thousands of people to evacuate.

This week, authorities ordered visitors to leave Minnesota's remote wilderness area, where rangers estimated that 6,000 to 10,000 people were present. Many faced a difficult evacuation by boat and canoe due to the region's limited accessibility.

The smoke is spreading as an intense heatwave grips parts of North America, prompting air quality warnings from Minnesota and Toronto to New York. 

Forecasters expect the thick smoke to reach Washington, D.C., by Thursday.

Nationwide, about 48 large fires are burning across 15 states, drawing more than 16,800 personnel to fight the blazes.

Weather experts note the US could have wildfires throughout the summer until snow arrives.