Residents have been warned to stay indoors to avoid both the smoke and the extreme heat

Over 800 wildfires are burning through forests in Canada, prompting heavy smoke warnings for millions of Americans.

Wildfires in Canada are pouring thick clouds of smoke into the US and will usher in unhealthy air quality for millions of people in Northeast and Midwest.

Wildfires in Canada are pouring thick clouds of smoke into the US and will usher in unhealthy air quality for millions of people in Northeast and Midwest.

Heavy smoke from several large wildfires blazing in Canada and Minnesota is expected to engulf large swaths of the Midwest and Northeast U.S. this week, exposing millions of…

There are more than 830 wildfires in Canada as of Wednesday morning.

Wildfires in Canada and Minnesota are sending heavy smoke to the Midwest and Northeast U.S., causing poor air quality alerts.

A massive plume of smoke from wildfires burning across Canada has swept into the United States, degrading air quality across the Midwest, Northeast and Mid-Atlantic.

Around 100 million Americans could be affected by the wildfire smoke, though impacts will vary by location

Environment Canada has issued health warnings after sky over city turns yellow

More than 830 wildfires are burning across Canada, with over 100 considered out of control.

Over 100 wildfires are burning in Canada, with winds carrying the smoke southeast. Warnings about unhealthy air extend from Minnesota through Toronto and into New York.

Warnings about dangerous, unhealthy air extended Wednesday from Minnesota through Toronto and into New York.

Warnings about dangerous, unhealthy air extended Wednesday from Minnesota through Toronto and into New York.

The smoke from the wildfires in northern Ontario is expected to linger around until Friday. Check where and how it's moving here.

Residents have been warned to stay indoors to avoid both the smoke and the extreme heat

TORONTO/NEW YORK: Toronto’s air quality ranked the worst among major cities globally on Wednesday as wildfire smoke from northwestern Ontario blackened skies and spread into the…

More than 830 wildfires were burning in Canada on Wednesday, along with more than a dozen in northern Minnesota, forcing mandatory evacuations.

Roughly 100 wildfires are raging out of control in Ontario, sending smoke streaming more than 1,000 miles from their origin.

A thick orange haze hung over Toronto on Wednesday 15 July as smoke from wildfires in northwestern Ontario engulfed Canada's largest city, giving it the worst air quality of any…

Wildfire smoke is dense enough in a handful of states that experts recommend masks for those who can’t stay indoors.