Traffic on a major east-west highway from Redding to the California coast crashed to a halt Monday and is not expected to resume until at least the middle of next week.
A steep hillside 28 miles west of Weaverville slid onto Highway 299, dumping rocks as big as a small house and enough material to fill 5,500 dump trucks, said Trisha Coder, a spokeswoman for the District 2 office of the California Department of Transportation.
The debris completely covered a catchment area, where crews were hoping to trap the sediment before it slid across the roadway and closed the primary route between the northern Sacramento Valley and California's northwest coastline.
"It's pretty crazy what Mother Nature can do," Coder said.
Kevin Erwin, of Weaverville, was driving to work in Willow Creek when the slide began. He captured the action in a 2.5-minute video, which he posted on YouTube.
The area at Big French Creek, 4.5 miles west of Big Bar, has been trouble-prone for a year, Coder said. Slides closed the road a year ago, and again on November 14. Crews were able to open the highway to through traffic just before Thanksgiving.
Coder said the material on the steep slopes above the Trinity River is particularly susceptible to moisture. After five years of low precipitation, this winter's heavy rains have inundated the soil, causing it to shift.
The first slide on Monday came at 10 a.m. amid rain. By 1 p.m. crews had it cleared enough to allow one-way traffic. Then the hillside slid again.
"Every time it storms that hill shifts a little. We can't have crews working in there until it's stabilized," Coder said.
Weather predictions for Dec. 19 offer the first opportunity to return to the slide site with geologists, who will evaluate the hillside and determine the next course of action. The long-term plan is to wait until late spring, when the soils should be drier, to develop a more permanent strategy for keeping Highway 299 open.
Caltrans has already spent $3 million on the Big French Creek slide and requested emergency construction funds. The agency expects to invest another $6 million before it comes up with a permanent solution, Coder said.
Local residents have reported little impact from the closure. Most are using back roads through the Six Rivers and Trinity national forests to get around the slide, said Rion Aslin, shop manager for Down River Towing Co. in Big Bar.
"It takes 30 or 40 minutes longer, but we can always get through," Aslin said, who praised Caltrans for keeping a close watch on the roadway and halting traffic at any sign of danger.
Local people know the area is slide-prone and take precautions, said Coder.
"They actually seem relieved that it's closed rather than having it open for them to take their chances," she said.
The closure has a far greater impact on tourists driving from the Pacific coast to the Redding area. The closest alternative route is Highway 36, which adds around 90 minutes to a one-way drive. Using Highway 20 to the south or Interstate 5 to the north through Grants Pass, Oregon, takes even longer, she said.
Caltrans will make every effort to open the highway before Christmas to at least one-way traffic, Coder said.