New Forecast Shows Heavy Snow Returning to Major Highways Already Hit by Up to 20 Inches

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More than a foot of early snow now covers the high country, and drivers heading into the mountains this week face the first chain control signs and seasonal pass closures of the winter. California’s three-level chain control system can require drivers to fit chains even on some all-wheel drive vehicles, depending on road conditions, according to Caltrans.

Snow Totals Across The Sierra

The heaviest snow from the Halloween weekend storm fell at the highest elevations. The National Weather Service in Sacramento forecast up to 10 inches above 7,000 feet and up to 18 inches on the tallest summits, while the Record Courier reported nearly 2 feet near the top of the East Fork on the Nevada side, Active NorCal reports. Flurries reached as low as 5,500 feet. On the eastern side of the range, Mammoth Mountain reports 12 to 20 inches across the mountain, 9 to 15 of them from the weekend storm alone, according to Fox Weather.

Next Week’s Forecast For The Sierra

The National Weather Service in Reno expects dry, mild conditions through the weekend, with Sunday highs in the low to mid 60s in Sierra communities, before what its forecast discussion calls “a significant pattern change” around Veterans Day on Wednesday, Nov. 11.

Forecasters note that the latest Climate Prediction Center guidance shows a moderate, 40 to 60 percent risk of heavy snow in the Sierra from Nov. 12 to 15, and that an atmospheric river tool projects a good amount of moisture heading toward the region in the second half of next week. Model solutions still diverge on the details, so amounts and timing remain open, but the office advises planning for wetter, cooler and windier weather late next week.

Mountain Pass Closures And US 395

With that snow on the ground, Mammoth Mountain moves its opening date up by a week to Thursday, Nov. 5, according to Fox Weather, bringing early-season skiers to the eastern Sierra just as winter restrictions return to several high-elevation routes.

Caltrans fully closed Sonora Pass on SR 108 and Monitor Pass on SR 89 during the storm, and Yosemite shut Tioga Road ahead of it. Chain controls went up on I-80 over Donner Summit, US 50 over Echo Summit and SR 88 over Carson Pass, where controls were still in place Sunday afternoon from east of Ham’s Station to five miles west of Picketts Junction.

For drivers coming from the west, US 395 is the main road along the eastern side of the range. With Tioga unlikely to be an option this late in the year, the drive from Sacramento to Mammoth Lakes runs about five and a half hours via US 50 and US 395, according to Active NorCal, which puts Echo Summit and its chain controls on the main route. Pass status changes with each storm, so Caltrans points drivers to its QuickMap or the CHIN line at 800-427-7623 before setting out.

California Chain Control Levels

Under R-1, passenger cars and light-duty trucks under 6,000 pounds with snow tires on at least two drive wheels are exempt from installing chains but must carry them. Under R-2, four-wheel and all-wheel drive vehicles with snow-tread tires, marked M+S, M/S or MUD AND SNOW on the sidewall, on all four wheels are exempt from installing chains but must carry traction devices, while every other vehicle needs them fitted. Under R-3, all vehicles must use chains or traction devices, with no exceptions, though Caltrans notes that a highway is often closed before R-3 is imposed.

Caltrans sets the speed limit at 25 or 30 mph whenever chains are required, and the California Highway Patrol can cite drivers who pass a chain-up sign without fitting them. Chains go on only after pulling completely off the road to the right, never in a traffic lane, and come off only after the “End of Chain Control” sign.

This story was originally published by Autoblog on Nov 5, 2026, where it first appeared in the News section. Add Autoblog as a Preferred Source by clicking here.