Canadian wildfire smoke triggers air warnings across US PHOTO

Thousands of visitors have been ordered to evacuate a vast, remote wilderness area in Minnesota as spreading blazes and drifting Canadian wildfire smoke trigger hazardous air quality warnings across the U.S. Midwest and Northeast.

More than 100 active wildfires are currently burning across Canada. Highlighting the immediate danger, a train crew in northern Ontario recently filmed themselves surrounded by encroaching flames before being safely evacuated. Driven by prevailing winds, heavy smoke from these Canadian fires is moving southeastward across the border, AP reports.

By Wednesday, unhealthy air quality warnings stretched from Minnesota through Toronto and into New York, coinciding with forecast projections of unusually high summer temperatures.

Tyler Hasenstein, a meteorologist with the National Weather Service in Chanhassen, Minnesota, urged residents to remain indoors to mitigate exposure to both the dense smoke and the sweltering conditions. "Those two things coinciding with each other is not good from a health perspective," Hasenstein warned.

The crisis has severely impacted far northeastern Minnesota, where forest rangers scrambled to enforce an emergency closure of the Boundary Waters Canoe Area Wilderness on Tuesday. The closure was prompted by approximately 17 lightning-sparked wildfires that began more than a week ago and continue to sweep through the 1.1-million-acre (445,000-hectare) preserve—an area nearly the size of Delaware that is accessible almost exclusively by watercraft.

Superior National Forest spokesperson Joy VanDrie estimated that between 6,000 and 10,000 visitors were inside the wilderness area when the evacuation order was issued. Operating across the region's vast network of lakes and waterways, rangers had successfully evacuated an estimated 90% of the occupants by Wednesday, July 15. No injuries or fatalities have been reported.

The evacuations come amid an exceptionally active and destructive fire season in the United States. According to the National Interagency Fire Centre, roughly four dozen major blazes are burning across 15 states, including North Carolina, Colorado, Utah, Idaho, Oregon, California, and Minnesota. Experts point to a combination of prolonged regional drought and record-low winter snowpack levels as the primary catalysts driving the rapid expansion of this season's fires.

By Tamilla Hasanova