July 22 (UPI) -- The massive Bootleg Fire in Oregon has grown to almost 400,000 acres as firefighters struggle to expand containment of the blaze, officials said Thursday.
The wildfire, which is the largest burning in the United States, grew on Wednesday but firefighters said they were aided by favorable weather conditions.
The fire, located in the Fremont-Winema National Forest in southern Oregon, has so far blackened more than 600 square miles and was 38% contained early Thursday.
Officials said cooler temperatures and calm winds allowed crews to slow the fire's growth over the past two days.
"We basically caught a break in the weather," Marcus Kauffman, a spokesman for the Oregon Department of Forestry, told The Oregonian.
The fire, though, has resisted most man-made efforts to slow it down and has continued to jump perimeters of treeless dirt and fire retardant.
"This is not going to return to normal anytime soon," said Doug Grafe, chief of fire protection at the Oregon Department of Forestry, according to USA Today.
Officials have banned all campfires starting Thursday, and only small propane cook stoves will be allowed into state parks and state-managed forests.
The Bootleg Fire, which started on July 6, is now Oregon's third-largest fire in history and has forced more than 2,000 people to evacuate. It's also destroyed more than 65 homes.