Dense smoke from major wildfires burning in Canada and Minnesota is expected to blanket large parts of the U.S. Midwest and Northeast this week. Millions of people are being exposed to dangerous air pollution as the smoke drifts southeast on the wind.
Air quality warnings stretched from Minnesota through Toronto to New York on Wednesday, while unusually hot summer temperatures added another layer of risk. Tyler Hasenstein, a National Weather Service meteorologist in Chanhassen, Minnesota, said the safest move is simple: stay indoors to avoid both the smoke and the extreme heat.
“That those two things coincide is not good from a health perspective,” he said.
Boundary Waters campgrounds face a difficult evacuation effort
In northeastern Minnesota, rangers were trying to alert people that the Boundary Waters Canoe Area Wilderness had been closed because about 17 lightning-caused fires were burning around the vast protected area. The wilderness is reached mainly by canoe, which makes evacuation slow and difficult.
The 445,000-hectare area, about the size of Delaware, was closed Tuesday, and officials estimated that 6,000 to 10,000 people were still inside. Joy VanDrie, a spokesperson for the Superior National Forest, said leaving can mean hours of paddling or even carrying boats over land.
| Location | What officials reported | Why it matters |
|---|---|---|
| Boundary Waters Canoe Area Wilderness | Closed Tuesday; about 17 fires nearby; 6,000 to 10,000 people inside | Evacuation is hard because access is mostly by canoe |
| Canada and Minnesota | More than 100 fires burning in Canada, plus major fires in Minnesota | Smoke is spreading across state and national borders |
| Midwest and Northeast U.S. | Warnings stretched from Minnesota to New York | Millions face unhealthy air |
VanDrie said she did not know when the area might reopen. Minnesota officials said some fires in Boundary Waters will be allowed to burn indefinitely, but they will be monitored to make sure they do not threaten people or property.
The Canadian Air Force also helped rescue two groups of young campers who had crossed the border and appeared safe, Minnesota Gov. Tim Walz said on Wednesday.
Dry heat is fueling a season already packed with fire risk
Dan Westervelt, an associate professor at Columbia University’s Climate School, said severe drought and heat in Canada and the United States have created “a perfect storm of really dry conditions that provide a lot of fuel for these wildfires to burn.” He noted that research shows rising temperatures from burning coal, oil, and gas make fires more frequent and more intense.
Fine particle pollution from wildfire smoke can be especially harmful to children and people with heart or lung conditions. It can cause shortness of breath, coughing, dizziness, or fatigue, and it can worsen heart and lung disease as well as other chronic health problems.
Experts recommend wearing an N95 mask if going outdoors is unavoidable and keeping indoor air cleaner by closing windows and using an air purifier or air conditioning.
The U.S. is already dealing with a particularly intense and deadly fire season. About four dozen large fires are burning in 15 states, from Minnesota and North Carolina to Colorado, Utah, Idaho, Oregon, and California, according to the National Interagency Fire Center.
Prolonged drought and record-low snowpack have combined to create conditions that allow fires to spread quickly. More than 16,800 people have been assigned to fight fires across the country, and the blazes have burned more than 9,138 square kilometers, or 5,678 square miles, an area larger than Yellowstone and Grand Canyon national parks combined.
Officials warn the smoke and fire could last for months
Officials in Minnesota warned that the major fires could burn for months. In Minneapolis, the high on Wednesday is expected to reach 36 Celsius, or 96 Fahrenheit, with temperatures above 32 C, or 90 F, forecast for the rest of the week.
Patty Thielen, director of the state Department of Natural Resources, said it could be a long stretch before the danger eases. “Well could be that we have major fires all summer until we get snow. Snow would be a good thing,” she said.
Air quality problems were also expected to last for days in Michigan and Wisconsin, and residents as far away as Maine reported a yellowish and brownish sky. The smoke could even reach Washington, D.C., by Thursday midday.
The Associated Press reported that Susan Montoya Bryan and Jeffrey Collins contributed to the story.
