GRANTS PASS, Ore. — A second home has burned in a fire on the flanks of Mount Hood outside The Dalles, where the winds that make the Columbia Gorge a destination for windsurfers are making the job of corralling a wildfire tougher for firefighters. The cost has already topped $1 million.

Oregon Department of Forestry spokesman Dave Morman said Tuesday the Government Flat Fire doubled to 10 square miles and one of about 50 homes evacuated in the area of canyons 10 miles southwest of The Dalles burned on Monday. Five other structures have burned.

“That’s one of the challenges when the fire gets into these long canyons, it’s very, very difficult for firefighters,” he said. “When it gets in those side draws, you can try, but you have problems with rolling debris. The fire easily spreads on those slopes, and then you get a 30 mph wind.”

With 714 personnel and seven helicopters fighting the fire, the cost has hit $1.4 million after four days, Morman said. Many are structural fire crews called in from surrounding counties after the governor declared the fires a conflagration.

Helicopters used to douse spot fires and air tankers used to stop the spread of flames during the early stages of a fire are generally the most expensive part of fighting wildfires.

Nationally, federal agencies have spent more than $1 billion so far, about half last year’s total of $1.9 billion, according to the National Interagency fire Center in Boise, Idaho.

The Government Flat fire burned within a quarter-mile of the water treatment plant providing drinking water for the city’s 12,000 residents, but crews were stationed to protect the facility, he said.

The fire started from lighting that ignited three separate blazes on Friday. Two of those have been brought under control, but the third, known as the Blackburn fire, continued to spread through timberlands, ranches and orchards interspersed with canyons on the northern flanks of Mount Hood.

A community meeting was set for Tuesday night at 6:30 p.m. at the Mid-Columbia Fire and Rescue headquarters at 1400 West 8th St. in The Dalles to keep residents informed about the fire.

Elsewhere, thunderstorms were predicted for Wednesday in southwestern Oregon, where firefighters continue to make progress on blazes burning in timber.

Evacuation alerts were lifted on the Douglas complex, made up of four fires burning across 76 square miles in an area seven miles north of Glendale. Containment was at 78 percent, with full containment projected for Sept. 1.

The Big Windy complex remained 20 percent contained as it burned across 36 square miles of federal forest in the Rogue River Canyon 25 miles northwest of Grants Pass. Whitewater rafters were able to float through the fire area, but the primary shuttle route, Bear Camp Road, remained closed.

The Labrador fire along the Illinois river 13 miles northwest of Cave Junction has burned 3.2 square miles, with no containment in sight.