Undaunted by high winds and triple-digit temperatures, firefighters are battling wildfires across eastern Washington, including a blaze that was threatening as many as 50 homes.

A lightning storm that swept through the Cascade Range and across eastern Washington sparked dozens of fires Friday.

Elsewhere in the parched West, California firefighters struggled to surround a 16,600-acre wildfire in Los Padres National Forest, but managed to fully contain a week-old 35,000-acre blaze in the Eastern Sierra.

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Santa Barbara County health officials issued an advisory because of smoke. Nearby residents were urged to limit outdoors activities and said people with asthma and other respiratory diseases should be cautious.

Firefighters moved closer to containing several fires in Utah, including the largest one in state history. That fire, about 120 miles south of Salt Lake City, had reached 568 square miles by Friday and was 75 percent contained.

A new wildfire near Boise, Idaho, forced authorities to briefly shut down a section of U.S. Highway 12. The blaze, which reportedly started when a passing tractor-trailer blew a tire, grew to more than 3,000 acres, or about 4 1/2 square miles, by late Friday night, Nez Perce County Fire Chief Ron Hall said.

Meanwhile, additional fire crews arriving in Idaho helped fire managers get the upper hand on several large wildfires elsewhere in the state, officials said.

In the central part of Washington state, a fire near Grand Coulee burned a summer home and several smaller structures while a separate blaze threatened several homes near Asotin, in southeast Washington.

High winds, scorching temperatures and low humidity hampered firefighters' efforts, but many fires were contained early. The National Weather Service issued a red-flag warning for high fire danger for all of eastern Washington.

Between 40 and 50 houses were threatened in Benton County in the south-central part of the state. Homeowners were initially told to evacuate, but most returned to help defend their property Friday night, said Steve Sautter of the county's Emergency Management office. No structures were reported damaged and the fire was 50 percent contained late Friday.

Benton County declared a fire emergency, a move that brought state assistance. Sautter said 175 to 200 firefighters would be arriving overnight from around the state.

Three fires had scorched about 6 square miles of native shrub-steppe habitat in the Hanford Reach National Monument near the Hanford nuclear reservation, while fires had burned about 3 square miles of the Columbia National Wildlife Refuge to the north.

In northeast Washington, firefighters knocked down 25-30 lightning-sparked blazes stretching from south of Spokane to the Canadian border, said Steve Harris of the state Department of Natural Resources. They ranged in size from one-tenth of an acre to 25 acres, though the biggest had burned mostly wheat.

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