Up to 12 inches of snow is forecast along the highest peaks this weekend under winter weather advisories from the National Weather Service, with gusts as high as 50 mph and the heaviest snow expected late Saturday night. Forecasters are telling drivers to plan on slippery roads, and for anyone heading over the passes the bigger question is likely to be which level of chain control goes up and whether their vehicle is exempt from it.
Snow Totals By Elevation
Four advisories from three offices run from 11 a.m. ET Saturday to 10 a.m. ET Sunday, a window that takes in the switch from daylight saving time early Sunday morning.
The NWS Reno advisories split the eastern side of the range by elevation. In the Greater Lake Tahoe Area, including Truckee, South Lake Tahoe, Tahoe City, Incline Village, Stateline, Glenbrook and Markleeville, snow is limited to elevations above 7,000 feet, with 2 to 5 inches and up to 9 inches along the highest peaks. Gusts there could reach 50 mph. Mono County, covering Mammoth Lakes, Lee Vining, Bridgeport and Coleville, gets 3 to 6 inches above 8,000 feet and up to 12 inches on the highest peaks, with gusts to 45 mph that could bring down tree branches.
NWS Sacramento covers the Northern Sierra above 7,000 feet, including Highway 50 and Interstate 80, with up to 8 inches and up to 12 inches at the highest peaks, plus up to 2 inches possible down to 6,000 feet. Snow levels start at 7,000 to 8,000 feet on Saturday and lower to 6,000 to 7,000 feet Saturday night, with the heaviest snow from Saturday evening into Sunday. Carson Pass, Kingvale and Donner Peak are inside the advisory.
Farther south on the western slope, NWS Hanford expects 4 to 7 inches between 7,500 and 9,500 feet and up to 11 inches above 9,500 feet across Yosemite outside the valley, Kings Canyon and Sequoia national parks, the upper San Joaquin River and Kaiser to Rodgers Ridge. Tuolumne Meadows, Wawona, Shaver Lake, Huntington Lake, Lodgepole and Giant Forest all sit inside it.
How California Chain Controls Work
Caltrans posts chain controls in three levels, and the difference between them decides whether a car keeps moving or stops at the side of the road. Under R-1, chains are required on everything except passenger vehicles and light-duty trucks under 6,000 pounds gross weight that have snow tires on at least two drive wheels. R-2 drops that exemption for most cars and leaves it only for four-wheel-drive and all-wheel-drive vehicles with snow-tread tires on all four wheels. R-3 requires chains or traction devices on every vehicle, with no exceptions.
For Caltrans, a snow tire is identified by its sidewall, which must carry MS, M/S, M+S or the words “mud and snow.” Many all-season tires on new cars carry an M+S marking, so a crossover that left the dealer on its original tires may already qualify under R-1 and, with all-wheel drive, under R-2.
AWD Still Has To Carry Chains
The exemption does not mean leaving the chains at home. Caltrans requires four-wheel-drive and all-wheel-drive vehicles to carry traction devices in chain control areas, and vehicles running on snow tires under R-1 have to carry chains as well. Drivers who skip chains when they are required can be cited by the California Highway Patrol and fined.
Once chains go on, the speed limit drops to 25 or 30 mph, which stretches the time it takes to cross a pass in a weekend storm. Caltrans posts current chain controls on QuickMap, and the advisories point drivers to 511 for road conditions in the state they are calling from.
Inside Yosemite, Tioga Road and Glacier Point Road are listed as open on the park’s current conditions page, last updated Oct. 23, with no overnight parking along either road or in their lots. The park’s road line at 209-372-0200 carries the latest status.
About the author
Adam Lynton
Co-Editor-in-Chief, Autoblog