More than 830 wildfires burning across Canada have pushed Toronto's air quality to the worst level globally, according to IQAir. Environment Canada issued health warnings Wednesday after the sky turned yellow, while a concurrent heatwave sent temperatures at Toronto's main airport runways to 55C.
The fires have destroyed the community of Collins and forced mandatory evacuations from several First Nations communities in northwestern Ontario. Residents of Namaygoosisagagun First Nation fled across Collins Lake with minutes' warning. Canadian National safely evacuated a train crew caught in a wildfire near Armstrong.
Thick smoke is expected to affect around 100 million people across the United States this week. Alerts stretch from Minnesota to New York, with the heaviest conditions forecast to reach Washington, D.C., by midday Thursday. Relief is expected later in the week as rain moves through the Upper Midwest on Friday and the Northeast on Saturday.