CHESTER Rolling rocks and flaming debris forced firefighters out of a canyon Tuesday night near Butt Valley Reservoir, where they were hoping to stop the Chips fire from its steady advance north toward Lake Almanor.
"The fire made a pretty substantial run. And it was moving fast very fast," said Alissa Tanner, a Chips fire information officer.
The fire, which started July 29 on the Pacific Crest Trail near Belden, has burned 42,215 acres, most of it in the Plumas and Lassen national forests.
The spread of the burn along the west side of Butt Reservoir increased evacuation orders Wednesday from advisory to voluntary for residents of Canyondam and Big Meadows along Highway 89. Pacific Gas and Electric Co. officials closed Rocky Point Campground.
The communities of Prattville, Almanor, Almanor West and Almanor East Shore are under evacuation advisories.
Along Highway 70 in the Feather River Canyon, Rush Creek and the community of Seneca remain under mandatory evacuation, while residents between Tobin and Twain are under a Plumas County sheriff's advisement to develop a family evacuation plan. This area includes Belden, Maggie's Trailer Park and Little Haven.
The Chips fire is threatening a total of 940 structures, Tanner said.
Firefighters were tested by an arm of the fire spreading up Red Hill, a former lookout near Highway 70.
"It's a really rough piece of ground. The fire gets under rocks and doesn't want to come out," Tanner said.
Crews spent the last three nights building containment lines that hopscotch along dirt roads from Humbug Valley east to Butt Reservoir. Designed to keep the fire west of the reservoir, they are holding well so far, Tanner said.
The thunderstorms and high winds predicted for the rest of the week will be a real test, she said.
"If we get through the next three days, we'll be looking good," Tanner said.
North of Lake Almanor in Lassen Volcanic Park, the Reading fire has burned nearly 24,000 acres, 6,622 acres of Lassen National Forest land near the communities of Old Station and Hat Creek. Officials expect it to spread northwest over West Prospect Peak and north over Badger Mountain down the Hat Creek drainage.
Sparked by lightning July 23, the fire is 23 percent contained. Full containment is expected Tuesday.
The state's largest wildfire is in Lassen County 40 miles northeast of Susanville. The Rush fire, sparked Sunday by lightning, has burned more than 96,000 acres of sage and juniper habitat in an area used by sage grouse and wild horses.
It is threatening a major natural gas line and transfer station, and power transmission lines that supply the Reno area.
The Rush fire is 40 percent contained, with full containment expected Sunday.