A "significant winter storm" has triggered an avalanche warning "for the Sierra Nevada mountains of California and Nevada, from Yuba Pass to Ebbetts Pass, including the Lake Tahoe Basin," the National Weather Service announced Tuesday morning.
The warning, which the NWS released at 6:57 a.m. PT Tuesday, is set to go into effect at 4 p.m. today and to continue to 7 a.m. Thursday.
Saying that the avalanche danger is "high in all areas," the NWS says that "a significant winter storm will impact the Sierra today through Thursday morning. Avalanche hazard will quickly rise to high as snow rates approach 3 inches per hour later this afternoon and evening."
"Wind slab and storm slab avalanche problems will be very likely at all elevations throughout the region," the NWS says, but notes that the warning does not apply to "ski areas or mountain highway corridors where avalanche mitigation programs exist."
According to the Sierra Avalanche Center, slopes 35 degrees and steeper pose the greatest danger, but the NWS still cautions that "avalanches may run long distances, into flat areas, and can run into mature forests."
CBS 5 reports that conditions will "deteriorate through Tuesday afternoon." Snowfall totals across the Sierra through Mono County could approach the 2 to 4 feet range by Thursday morning, and 1-2 feet of snowfall have been predicted at lake level.
That, plus the "strong and gusty winds" (up to 45 mph) expected to develop later Tuesday evening could create "treacherous and dangerous driving conditions with white-out conditions and zero visibility." Because of that, drivers are warned to avoid travel in the area if at all possible.