MINNEAPOLIS — A rapidly expanding wildfire in Minnesota's north woods spread a plume of smoke across the Upper Midwest on Tuesday, with haze smudging the sky as far away as Chicago and Milwaukee, where the Brewers closed their stadium roof before a night game.
The haze was heavy enough that some people reported burning eyes and difficulty breathing in the Chicago area, about 600 miles south of the forest fire, the National Weather Service said.
The plume came from a fire in the Boundary Waters Canoe Area Wilderness, a lake-dotted region along the Minnesota-Canada border, that grew swiftly this week to cover nearly 160 square miles. No structures have burned and no one has been hurt, officials said.
The residents of Isabella, a small town of about 200, were standing ready to evacuate if needed.
The fire started Aug. 18 with a lighting strike 20 miles from Ely, but only began spreading quickly this week in windy, dry conditions. The fire raced 16 miles east in a single day from Monday to Tuesday.
"Nobody would have guessed it would be doubling and quadrupling in size," said Jean Bergerson, a spokeswoman for the Minnesota Interagency Fire Center.
Winds up to 25 mph forecast for Tuesday and Wednesday were likely to spread the fire, dubbed the Pagami Creek fire for its point of origin, further. She predicted it would be days or weeks before the fire was under control.
The Wisconsin Department of Natural Resources agency's air quality monitor showed a spike in particle pollution throughout the day in the southeast part of the state including Milwaukee, and it issued an air quality alert for sensitive groups in the area.
The haze forced Miller Park officials to close the stadium's roof before the Milwaukee Brewers took the field for a game against the Colorado Rockies, park officials said. The smoke also reached Michigan, where forecasters said it rode northwesterly winds from a cool front.
Jim Richardson, a forecaster for the National Weather Service in Minnesota, said it wasn't unusual for the plume to spread so far, noting that smoke from Arizona's massive wildfire in May reached Minnesota. Richardson said changing winds Wednesday may shift the plume more directly south of the blaze.
The Boundary Waters is a wild region popular with canoe campers for its beauty. Several lakes and entry points into the wilderness were closed, and about 120 campers were evacuated from the fire zone earlier this week, some by Forest Service float planes.
About 36 residences on the eastern edge of the fire were evacuated Monday night.
In Isabella, residents were told earlier this week to have their medicine, valuables and pets close by so they could leave on short notice, Bergerson said.
Tom Person, co-owner of the Stony River Cafe in Isabella, said he had been there 29 years and this was the closest a forest fire had gotten to town. He said it looked like a huge white thunderhead rising out of the woods about 10 miles from town.
"It's quite a sight," Person said. "You can see it and smell it when the winds are right."
The cafe was open Tuesday, but Person said he was prepared to go if the winds changed and sent the fire roaring back toward town. "That's just common sense," Person said.
About 200 firefighters were assigned to the fire on Tuesday and more were pouring into the area. Bergerson said the first of a group of about 50 elite firefighters were coming in from the Rocky Mountains and would probably take over on Thursday.
Gov. Mark Dayton announced Tuesday that he was sending in four Minnesota National Guard helicopters equipped with huge buckets for water drops to assist the firefighters.
Meanwhile, the Northland Chapter of the American Red Cross announced it was moving cots, blankets and food to the Community Center in Finland to accommodate evacuees.
With the winds calming somewhat, ground crews were patrolling the north side of the fire on Tuesday. Bergerson said stronger winds on Monday prevented attacking the fire on foot and made canoe travel difficult. Downdrafts from the fire were creating more than 3-foot waves on some lakes as it passed.
While the Pagami Creek fire has grown quickly it has done less damage so far than the 2007 Ham Lake fire, which burned 118 square miles in Minnesota and Canada and destroyed nearly 150 buildings worth more than $10 million. It was the most destructive fire in the state since 1918.
Sections of the Boundary Waters Canoe Area Wilderness, remain open, but Bergerson recommended that campers call ahead as many entry points and lakes have been closed due to the fire.
Associated Press writer Colin Fly in Milwaukee contributed to this report.