SONORA, CALIF., SEPT. 4 -- When Helen Wann opened her door to the sheriff's deputy late Tuesday night, she could see the dull red glow at the top of the hill, smell the ash and hear pines and white fir cracking in loud pops from the intense heat.

The biggest of the West's 1,800 fires was descending on her 40-year-old frame house. Tiny and determined, a longtime mountain resident, she had worked out her priorities long ago.

Her husband, Trenton, tossed his guns into the Chevy. She gathered three of her cats, Molly, Sara and Calico. And together they left, not looking back. The next day, a team of sweating young firefighters managed to divert the path of the blaze just 300 yards from their door, one small victory in a war of heat and smoke that has consumed the West and has no end in sight.

U.S. Forest Service Chief Dale Robertson in Washington said this week's western holocaust is "one of the worst . . . we have had in more than 30 years in these states."

More than 375,000 acres of forest and brush in California have burned in just seven days. The total for the entire West in a firestorm without recent precedent is approaching 500,000 acres in seven states, with little relief in sight.

Nearly every available firefighter in the country, many of them students drawn to a lucrative, if exhausting, summer job, are struggling to contain some of the more than 1,800 fires as erratic winds and highly charged clouds threaten to start more.

The Wanns today sat at a picnic table in a make-shift evacuation center sheltering 800 people at the county fair grounds. A coffee- colored haze hung over this little county seat as the ash from hundreds of lightning fires left the Sierra Nevada looking like a bad day in Los Angeles.

"We feel a little tired, that's about it," said Trenton Wann, 69, a retired lumber company boiler fireman. Their grandson took Helen back to check the house today. It was fine, as were the two outdoor cats, Pug and Pesty, a testament to the success so far in preserving life and residential property amid such wide destruction.

Forest service officials still report only one death, a firefighter hit by a motorcycle, and at least 61 injuries, most of them minor. About 50 homes, mostly isolated cabins and trailers, have been lost in California and Oregon, the hardest-hit states.

California forestry department director Gerald Partain said Thursday that just the fires here in Tuolumne County, near the northern entrance to Yosemite National Park, "could go as high as 200,000 to 300,000 acres" before they are contained. This afternoon they passed the 100,000-acre mark.

In a foothill county of 43,000 people where many lives are tied to the timber industry, this is devastating news. Just when the new construction boom was reviving the economy here, "this could have a serious impact on us," said county supervisor Greg Hurt, a Sonora tire store owner.

Rena Briggs sat with two of her sons, playing a board game and thinking of the ramshackle house in Sugar Pine they were forced to vacate Wednesday night. The house, 15-year-old Brian Briggs noted, "is junk." "If it burns," his mother agreed, "I hope it burns to the ground." They have insurance. What concerns her far more is her husband's job as a logging truck driver. "This cannot be good for the timber industry," she said.

Firefighting officials here reported California Air National Guard C130 aircraft dropped bright orange fire-retarding chemicals on blazes approaching the Wann's house and others in Tuolumne City 10 miles east of here. Several hundred firefighters, including crews from New Mexico who drove two days to get here, have been setting backfires and cutting brush-free fire breaks with bulldozers to protect livestock and ranch buildings near Tuolumne.

The Paper-Cabin fire, as the main blaze here is called, traveled up the steep Tuolumne River canyon, where blinding smoke and sheer walls prevented effective fire-fighting.

Hurt estimated that 4,000 local residents, nearly 10 percent of the county's population, have had to evacuate their homes for shelter with friends and relatives, or public facilities such as the one in Sonora. Despite reports that many California residents were resisting evacuation orders, Hurt said officials here made sure people moved out of endangered areas. Officials also closed two main roads: Rte. 108 at Twain Harte and Rte. 120 at Moccasin.

Hurt and other local residents said they were encouraged by Thursday night's relatively calm winds, but the tinder and heat of a lengthy drought still leave an enormous fire danger.

This area is a popular refuge for residents of the booming Central Valley towns of Modesto, Sacramento and Fresno. The foothills are full of cabins and trailers maintained for occasional visits, many of which will have to be canceled this Labor Day weekend.