DULUTH – The Greenwood fire burning in northeastern Minnesota's Superior National Forest doubled in size Monday, stretching to some 30 square miles.
As teams fight the state's largest wildfire, four new smaller fires started Monday within the Boundary Waters Canoe Area Wilderness, and a fire at the edge of Ontario's Quetico Provincial Park moved closer to the Canadian border.
Officials extended the BWCA closure another week, to Sept. 3, as a result.
Mapping of the Greenwood fire via an infrared flight Monday night showed how far the fire spread during its intense run northeast that afternoon, with a preliminary footprint of 19,493 acres. The drought-stricken rural Lake County region didn't get the rain Tuesday that other parts of northeastern Minnesota did, but cloud cover tempered the fire, said Clark McCreedy, public information officer for the interagency team managing the fire.
With such parched vegetation, "what we really need is a belligerent soaker of a rain," he said.
The fire created a pyrocumulus cloud — or fire cloud — visible for miles, with smoke and ash from the fire reported as far as Lutsen, about 30 miles east. On Tuesday, smoke from the fire permeated Duluth for several hours, and residents were advised to keep their windows closed.
Northern Minnesota hasn't seen a pyrocumulus cloud since the 2011 Pagami Creek fire, said Joe Moore, a meteorologist with the National Weather Service in Duluth.
The giant gray clouds are formed by fire-created hot air and smoke and can be dangerous to firefighters, causing gusty winds and lightning. The Weather Service did receive a report of lightning from the Greenwood cloud, Moore said, but couldn't confirm it.