Firefighters reported progress Saturday in their battle to contain a nearly 10,000-acre wildfire that destroyed 80 homes after being touched off by a spark from a lawn mower.

Crews expected to have the blaze fully contained by Monday evening.

"Everything is good news today, so far," said Roy Del Carlo, a spokesman for the state Department of Forestry and Fire Protection.

By midday Saturday, the fire had blackened 9,922 acres and destroyed 30 outbuildings and 10 vehicles in addition to the 80 homes, Del Carlo said.

The blaze was 80 percent contained and no longer threatening homes, he said. Most residents who were evacuated were being allowed to return to their property.

The fire began Wednesday when a lawn mower struck a rock in dry grass, setting off a blaze that cut erratically through the pine-and-oak-covered hills south of Shasta Lake, about 140 miles northwest of Sacramento.

Residents said they were puzzled by the way the blaze spared some homes while destroying others nearby. Del Carlo said 186 homes had been saved.

Officials said they do not have an estimate of how much damage the blaze caused but said the cost of fighting the fire will top $1.8 million.

In central Washington, firefighters worked to gain the upper hand on several wildfires Saturday as forecasters predicted new lightning strikes this weekend.

Lightning and thunderstorms were forecast in Clark, Skamania and Klickitat counties, Public Lands Commissioner Doug Sutherland said Saturday from Olympia, adding: "All of which worries all of us a lot."

A fire that covered more than 700 acres on Yakama tribal lands was under control and in the mop-up stage Saturday. A tribal dispatcher said that blaze started Tuesday.

Acreage numbers held steady in checks with fire officials Saturday but were expected to increase "because it was very active last night," said Carol Tocco, spokeswoman for the Northwest Interagency Coordination Center in Portland, Ore.

About 30 homes remained evacuated, with residents of 40 to 50 more homes put on notice that they might have to leave because of a blaze about 20 miles northwest of Wenatchee. The fire was estimated at 2,100 acres, fire information officer Stefani O'Connor said.

Northwest of Yakima, a fire was estimated at about 4,200 acres, and residents of 45 homes along the Naches River were on notice they might have to flee if the fire grew.

Bonnie Blumenthal, who lost her home in the fire, is embraced by neighbor Terry Mays, right, in Bella Vista, Calif.