Wildfires in Canada and Minnesota trigger poor air quality alerts across Midwest and Northeast US
Dramatic video shows a freight train in Canada surrounded by wildfire flames and workers requesting an emergency rescue as they report being "encased" in fire.
Around 100 million Americans could be affected by the wildfire smoke, though impacts will vary by location
Warnings about dangerous, unhealthy air extended Wednesday from Minnesota through Toronto and into New York.
Wildfires burning across Canada are producing vast smoke plumes that are traveling hundreds of miles south, degrading air quality far beyond the fire zones themselves.
