Residents of at least 150 homes in southeastern Washington were forced to evacuate as a fire that had charred at least 15,000 acres moved north out of the Umatilla National Forest (search) onto private land.

The leading edge of the fire, which had covered just 150 acres on Saturday morning, was about 10 miles south of this rural community, authorities said Sunday.

"At the moment it's zero percent contained, burning vigorously in timber, grass and brush," said John Townsley at the Northwest Fire Coordination Center in Portland, Ore.

The cause of the fire was not yet known. No lightning strikes were reported in the area Friday, when it started in tinder-dry conditions.

In central Washington, a 1,075-acre wildfire near Lake Wenatchee (search) 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. (search), 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 3,300 acres.

Montana highway officials reopened westbound I-90 on Saturday but travelers were told to expect restrictions as fire crews worked in the area between Alberton and Tarkio. For a time on Friday, about a 90-mile stretch of I-90 was closed. Officials reopened eastbound lanes Friday night.