The Colockum Tarps Fire has burned across more than 73 square miles of grass, sagebrush and timber southeast of Wenatchee in the Colockum Pass area. The fire was 5 percent contained, but the flames spread rapidly Tuesday, churning through dry fuels to the south, fire spokesman Peter Frenzen said.
The fire already has burned three primary homes and several outbuildings.
Residents of about 60 homes have been evacuated. Authorities were reviewing evacuation levels in some areas, particularly on the north end of the blaze, to see if some people could return home.
However, Frenzen said, authorities in Kittitas County were considering additional evacuations at recreation areas along the Columbia River as a precaution. Fire crews were focusing on protecting power lines, recreation areas, wind farms and some scattered homes south of the fire, he said.
Thunderstorms forecast for much of Eastern Washington later this week also are raising fears about high winds and lightning, which could spark even more fires.
"The winds and the thunderstorms are a concern, but on the plus side, we're also looking at the possibility of some moisture by Thursday," Frenzen said.
Dry brush and grasses and moderate winds were fueling the blaze. A so-called scoop plane, which flies low to scoop up water, and an air tanker were dropping water and retardant on the fire.
The fire started Saturday. The cause was under investigation.
Further south, about 1,300 firefighters were working to control a fire that has burned across 32 square miles around Satus Pass and closed Highway 97 between Goldendale and Toppenish.
The fire was 40 percent contained Tuesday. Evacuation levels were lowered for residents of 69 homes on the fire's sound end, allowing them to return home, said Bruce Livingston, a Washington Department of Natural Resources spokesman.
A perimeter containment line was established most of the way across the southern and western end of the fire, Livingston said, and crews were focusing on the eastern edge of the blaze.
The blaze ignited last Wednesday and the cause was under investigation.