Smoke from Minnesota-Ontario wildfires drives hazardous air

A dense plume of smoke from wildfires burning in northern Minnesota and western Ontario, Canada, is sweeping across the Midwest and Northeast United States and southern Canada, creating hazardous air quality and compounding a severe heat wave for millions of people. The smoke, which intensified on Wednesday, July 15, 2026, is expected to persist through at least Friday, triggering widespread health advisories.

In Minnesota, where several large fires are actively burning, the situation is most acute. Governor Tim Walz declared a peacetime emergency and deployed the National Guard to assist with fire mitigation and evacuations. The U.S. Forest Service closed all entry points to the Boundary Waters Canoe Area Wilderness. Air quality in northeastern parts of the state, including Two Harbors and the Tribal Nation of Grand Portage, reached the hazardous "maroon" category, the highest and most dangerous level on the air quality index. The Minnesota Pollution Control Agency issued an air quality alert spanning through Friday for much of the state.

Across the border in Ontario, hundreds of wildfires are burning, with 112 fires reported out of control nationally as of Wednesday morning....