A wildfire believed to have started in a burning mobile home had grown to more than 950 acres by Monday evening and threatened more than 140 homes, fire officials said.
Residents of 73 dwellings were ordered to evacuate and occupants of another 70 scattered homes in the area remained under notice they also may have to leave, Forest Service spokesman Robin DeMario said.
The blaze started late Saturday as a structure fire on private land and eventually spread to parts of the Okanogan-Wenatchee National Forest in central Washington.
The fire was reported 10 percent contained Monday evening, according to the Central Washington Area Incident Management Team. No other homes had been damaged as of Monday and no injuries were reported.
Firefighters were using hiking trails to help build fire lines, and helicopters and air tankers were dropping water and retardant, DeMario said.