RENO, Nev. - The first of back-to-back winter storms brought one foot of snow and an avalanche warning to the Sierra Nevada on Thursday, closing schools at Lake Tahoe and intermittently shutting down interstate traffic west of Reno.
A winter storm warning remained in effect through 4 a.m. Friday from Mammoth Lakes south of Yosemite National Park to about 200 miles north of Lake Tahoe.
A new storm watch follows Friday night through the weekend, with as much as 3 feet of snow possible at the highest elevations by Sunday, the National Weather Service said.
"Our next storm is still on track to be colder, slower and wetter than today’s storm," service forecasters in Reno said late Thursday.
Multiple spinouts and a jackknifed semitrailer on Interstate 80 west of Reno forced various closures throughout the day. Travel had resumed in both directions Thursday night but the California Highway Patrol warned the roads were slick.
"Personnel are still working hard in clearing multiple vehicles stuck over Donner Summit so slow down!!" highway patrol tweeted from Truckee, California, east of the I-80 summit.
Mount Rose Ski Tahoe reported about a foot (30 cm) of snow at the top of the resort southwest of Reno and at least 8 inches (20 cm) was reported 80 miles (128 km) north of Reno at Susanville, California, where 6 inches fell in just over two hours.
At Lake Tahoe, all schools were closed Thursday on the north shore at Incline Village and at South Lake Tahoe, California.
The Sierra Avalanche Center in Truckee issued a backcountry avalanche warning through Friday for the Central Sierra Nevada, including the Tahoe area.
"Feet of new snow and strong winds will overload an already weak snowpack and result in very dangerous avalanche conditions in the mountains," the center said.
The storm out of the Pacific Ocean roared ashore in Northern California early Thursday, bringing heavy rain that snarled the morning commute and prompted flood advisories in the San Francisco Bay Area and south into the Central Coast.
Wind speeds reached 40 mph with an isolated gust of 50 mph reported in the Marin Coastal Ranges, the National Weather Service office in San Francisco said. About a half-inch of rain fell from Vallejo to Sacramento.
Forecasters said much of interior Northern California could experience freezing temperatures early Friday, with sub-zero lows in parts of the Sierra and low-teens to single digits in some western Nevada valleys.
The service expected winds would gust Thursday night into Friday up to 40 mph (64 kph) on Lake Tahoe, producing waves up to 4 feet (1.2 meters), and gusts up to 70 mph over mountain ridges.
AP Writer Christopher Weber in Los Angeles contributed to this report.