A wildfire in northeastern Minnesota more than doubled in size Tuesday, growing to more than 19,000 acres, after it produced pyrocumulous clouds that generated lightning and even raindrops, fire officials said.
The Greenwood Fire's growth, most of which happened Monday afternoon, prompted firefighters to leave McDougal Lake, about 80 miles northeast of Duluth, officials said. Authorities fear that structures might have been destroyed or damaged.
"We had crews embedded, and as this fire took off, it was quite an effort to communicate with forces on the ground so they could get out," said federal fire incident spokesman Clark McCreedy.
The pullout was a success, and no injuries were reported. However, downed trees and necessary cleanup mean crews have been unable to assess damage around the lake, McCreedy said.
In addition to the firefighter pullout, 159 dwellings were evacuated Monday, according to an update from the National Wildfire Coordinating Group. Cabins, homes and recreational sites remain under threat, the group said.
Patrick Prochaska, a Minneapolis resident who built a cabin near McDougal Lake in 2012, told NBC affiliate KARE that he watched via security camera as flames mostly bypassed his property Monday, causing minor damage.
"I was feeling very scared," he said. "At the same time, I could see that it was not doing anything to the house, and it was kind of reassuring."
The fire in and north of Superior National Forest has mostly performed according to the weather, fire officials said. On Monday, with dry fuel on the ground and temperatures in the high 80s, it was an expanding inferno punctuated by strobes of lightning.
"The winds were drawn into the fire from all directions," the incident's fire behavior analyst, Michael Locke, said in a video update Tuesday. "It created what we call pyrocumulous clouds. And really high in the atmosphere ... you'd see a thunderstorm, and in fact they went high enough to produce a few sprinkles of rain and even some lightning."
Temperatures dipped into the mid-70s Tuesday, and the blaze mellowed. "The real story was cloud cover and cooler temperatures," McCreedy said.
More of the same, and possibly rain, was in the forecast, giving officials hope that they might be able to close the book on an unusually active and dry fire season in Minnesota.
Experts have said climate change has set the stage for extreme weather, including an increase in the frequency and intensity of wildfires in the Northern Hemisphere.
Firefighters — 426 were assigned to the Greenwood event — have been confronted with "prolonged, severe drought," making parts of Minnesota look like the fire-prone West this summer, McCreedy said.
The Greenwood Fire, which was detected Aug. 15, is believed to have been sparked by lightning.
So far, firefighters have scored no containment, and areas including McDougal Lake, Sand Lake and the Highway 2 corridor have been under mandatory evacuation orders. The federal Boundary Waters Canoe Area Wilderness was closed Saturday "due to active and increasing fire activity, extreme drought, limited resources," the National Forest Service said in a notice.
Officials set a goal of Sept. 1 for full containment.
"We're probably going to get more of that moderating weather for the rest of the week," McCreedy said. "That opens the door for fire crews to make progress on the ground."
CORRECTION (Aug. 25, 2021, 9:02 a.m. ET): A previous version of this article incorrectly described the location of McDougal Lake. It is about 80 miles northeast of Duluth, not 80 miles south-southwest.