Firefighters are hoping cooler, wetter weather in the next few days will help them contain a fast-moving wildfire (search) that burned at least 35 buildings and forced the evacuation of about 175 homes.

By late Sunday, the fire in southeast Washington (search) had grown to 32,000 acres from only 150 acres the day before.

The fire was about 10 miles south of this rural community. It had moved north out of the Umatilla National Forest to private land.

It was not clear whether the burned structures were homes, sheds or other buildings, said John Townsley, spokesman for the Northwest Fire Coordination Center (search) in Portland, Ore.

"Right now there is so much smoke that it's difficult to see very well," Townsley said.

Farmers beyond the flames were plowing up broad swaths of earth through fields of wheat and other crops, trying to create breaks to save this year's harvest, officials said.

Gov. Christine Gregoire accompanied State Patrol Chief John Batiste on a flight to the area Sunday evening to assess the fire, spokeswoman Althea Cawley-Murphree said.

Officials are not sure how the blaze began Friday, but ruled out a lightning strike, Townsley said.

A thick layer of smoke over the region grounded water tankers and helicopters for much of Sunday.

In central Washington, a 1,100-acre wildfire near Lake Wenatchee that had threatened 140 homes was 50 percent contained, said Patrick Lonergan, spokesman for the Central Washington Area Incident Management Team. He said he expected that fire to be fully contained by Wednesday.

Elsewhere, 10 houses near Alberton, Mont., were evacuated Saturday after a fire that started along Interstate 90 crossed over a ridge above the houses, officials said.

The fire was one of four that started Thursday along Interstate 90 in western Montana that had burned a total of 4,000 acres.

Montana highway officials reopened westbound I-90 on Saturday.