A snow blower attempts to clear the roadway on Interstate 80 near Kingvale on Jan. 15, 2022.
© Caltrans
A snow blower attempts to clear the roadway on Interstate 80 near Kingvale on Jan. 15, 2022.
Researchers at the UC Berkeley Central Sierra Snow Lab near Donner Pass said they recorded 21.5 inches of snow between Saturday and Sunday morning as a winter storm warning remains in effect until 10 p.m. Monday for the Sierra Nevada and Tahoe Basin.

"We are now 204% of average precipitation to this point in the water year (Oct 1 to Sept 30) and we have 92% of our average peak seasonal #Snow Water Equivalent (SWE)," the lab tweeted Sunday, noting the snow water equivalent refers to the amount of water that can be collected by melting the snowpack.

At least 7.5 feet of snow has fallen at the lab in the last week. Caltrans said about one inch an hour had fallen over Donner Summit from Friday through Sunday alone.

"It's still coming down hard out there!" the lab tweeted earlier on Saturday. "The snowpack is DEEP with ~10 feet (3 meters) of snow already on the ground!"

Over the weekend, The National Weather Service warned of blowing snow, whiteout conditions, traffic delays and tree damage, and people are discouraged from traveling as another one to two feet of snow is expected to accumulate through Monday morning.

"Hazardous mountain travel is expected," NWS Sacramento tweeted Sunday morning. "Carry chains, & check road conditions before you go!"

On Sunday afternoon, Caltrans said that heavy traffic had led to a two-mile backup on the westbound lanes of Interstate 80 from the state Route 267 junction to the chain control check point near exit 184 in Truckee. Though no incidents were reported, outbound South Lake Tahoe traffic also snarled U.S. 50 westbound from Country Club Drive to Echo Summit.

"Our crews are working hard to keep Sierra mountain passes clear this holiday weekend," Caltrans said. "Please take it slow in ice & snow and don't crowd the plow."