Ontario wildfires force evacuations as smoke chokes Toronto and Thunder Bay

More than 100 fires kept burning across Ontario on Thursday, forcing evacuations and sending thick smoke over Toronto and Thunder Bay. Ontario sought federal support for wildfire evacuations as the smoke spread east, while Toronto’s air quality fell among the world’s worst.

Thunder Bay said on July 15 that it was not at risk of evacuation, but the city’s Air Quality Health Index was at Very High Risk. That pushed officials to suspend all non-critical outdoor operations and programming, including outdoor pools, beaches, splash pads, golf courses and outdoor marina services.

The scale of the fire season stretched far beyond one city. More than 850 wildfires were burning across Canada, with roughly 135 active fires in northwestern Ontario and more than half a dozen new blazes there. NASA tracked Ontario wildfire smoke moving east, and that plume blanketed Toronto, where the air briefly became hazardous enough to place the city among the worst in the world for air quality.

Public Safety Canada’s July update on the wildfire season outlined federal coordination of support. The response framework puts local and provincial authorities first, before federal help is requested, and it can escalate to Operation LENTUS, the Canadian Armed Forces’ disaster-response role, if more resources are needed.

In May, the federal government warned that above-normal temperatures were expected for nearly all Canadian regions through June, July and August, with below-normal precipitation signals over northwestern Ontario. In February, Public Safety Canada announced an investment in stronger pan-Canadian aerial firefighting capacity after Canada’s second-worst wildfire season on record in 2025.

Health Canada and the Public Health Agency of Canada warn that wildfire smoke can affect everyone, with greater risk for young children, pregnant people, seniors, outdoor workers and people with lung or heart disease.