Ontario wildfires force First Nations evacuations as Toronto air quality hits world's worst
Smoke from hundreds of wildfires in northern Ontario blanketed Toronto on Wednesday, reducing visibility and pushing air quality to the worst among major world cities. First Nations communities have been evacuated, and the smoke is spreading across the US Northeast amid a record-breaking heat wave.
Air quality emergency in Toronto
Toronto recorded an Air Quality Health Index (AQHI) of 10+, the highest "very high risk" level, on Wednesday, July 15. The Swiss monitoring company IQAir ranked the city's air as the worst among major world centers, ahead of Kinshasa and Delhi. The smoke, emanating from wildfires in northwestern Ontario, turned the sky an orange-yellow and left a strong smell of wood smoke across the metropolitan area. Environment Canada warned that hazardous conditions could persist through Thursday night.
I expect that this will occur more frequently over the coming decades so cities and residents need to prepare for this in the future.
The poor air quality coincided with a record-breaking heat wave, with temperatures in downtown Toronto reaching 37.3C, breaking a three-decade high. Runways at Toronto Pearson International Airport recorded a surface temperature of 55C. Paula Oreskovich, a Toronto resident, expressed concern about the recurring smoke: "I think you have to be silly if you're not going to be concerned about climate change. It's definitely here, it's definitely happening, and it's happening..."
Communities evacuated, train caught in flames
More than six First Nations and rural communities around Thunder Bay were evacuated as flames advanced. The community of Collins (Namaygoosisagagun First Nation) was destroyed, with residents fleeing by boat across Collins Lake after only minutes of warning. Photographer Nadya Kwandibens wrote on social media: "My family hometown, Collins Ontario, is GONE."
An entire First Nation community has been erased because of this disaster.
Lise Vaugeois, the provincial representative for the region, confirmed that all residents escaped safely. "Collins has burned to the ground," she said. Meanwhile, a Canadian National train transporting flammable cargo became trapped by fire near Armstrong, Ontario; crew members reported being "encased in flames" in a widely shared video. CN suspended rail operations and evacuated employees and Armstrong residents on Monday night. Three other trains were held at a safer location.
Heat dome shatters records across US and Canada
A heat dome that originated in the Mountain West has spread into the eastern US and Ontario, shattering all-time temperature records. On Tuesday, Billings, Montana, reached 111F (44C), breaking the previous record of 108F. Salt Lake City hit 109F (43.9C), above the old mark of 107F. Ottawa reported a high of 100.4F (38C) and Toronto reached 37.3C (99.1F) downtown.
The climate system now is fundamentally different due to fossil fuel-driven climate change. Our atmosphere is much warmer.
In Montreal, smoke from fires in northern Quebec and Ontario turned the sky yellow on Tuesday morning. The heat and humidity are expected to worsen air quality, with the US National Weather Service warning that the most intense heat would arrive on Wednesday and expand into the Mid-Atlantic.
- Billings, MT
- 111 °F
- Salt Lake City, UT
- 109 °F
- Toronto, ON
- 99.1 °F
- Ottawa, ON
- 100.4 °F
Smoke suppresses storms, spreads south
Thick smoke from the Canadian wildfires significantly altered weather patterns across New England. The National Weather Service had issued an enhanced risk of severe thunderstorms for northern Vermont, New Hampshire, and western Maine on July 15, anticipating rotating supercells with large hail and possible tornadoes. However, the smoke layer blocked sunlight, reducing surface heating and storm fuel from modeled estimates of 3,000-3,500 units to only 1,500-2,000 units. A warm layer created by smoke at 30,000-40,000 feet also acted as a ceiling, suppressing thunderstorm updrafts. Only a late-night storm complex developed, bringing tennis ball-size hail to St. Lawrence County, New York, but little else.
- Canadian National evacuates employees and Armstrong residents as wildfire approaches.
- Billings, Montana hits 111F (44C), breaking all-time record.
- Toronto wakes to orange haze; Environment Canada issues very high risk air quality warning.
- IQAir ranks Toronto's air quality worst among major world cities.
- CN freight train caught in wildfire near Armstrong; crew safely evacuated.
- Smoke suppresses severe thunderstorm development over northern New England.
The smoke is forecast to push southward by Thursday, with air quality alerts issued across Michigan, Minnesota, and Wisconsin. In Boston, the smoke was dense enough to dent afternoon temperatures and prompted forecasters to cancel a planned heat alert, while vibrant sunsets are expected as particles scatter blue light.
Broader fire season outlook
The Government of Canada had earlier said that the 2026 wildfire season began more slowly than the record-breaking years of 2023 and 2025, but warmer-than-usual temperatures have since heightened the risk. As of Wednesday, 835 active fires were burning nationwide, with 112 classified as out of control, mostly in Manitoba, Saskatchewan, and Ontario. So far this year, 4.7 million acres (1.9 million hectares) have burned, less than a quarter of the 22.2 million acres scorched in all of 2025. Municipalities across Ontario have imposed open-flame bans, including campfires, as a precaution.
