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Winter Snow Warning: Up to 14 Inches of Snow Threaten California and Nevada Mountain Highways

By Adam Lynton Autoblog

May 26, 2026 4:20 AM

A late-season Pacific upper-level low is dropping into the West, and California's Eastern Sierra is back in the Weather Prediction Center's sights. WPC ensemble guidance shows up to ~14 inches of snow possible at the highest crest in the worst case scenario, with accumulating snow reaching into western Nevada. The official NWS Reno forecast issued at 235 AM PDT this morning projects more modest 4 to 8 inch totals across Mono County, Sonora Pass, Tioga Pass, and Mammoth Mountain, with higher amounts confined to the highest peaks. Either way, fresh Winter Weather Advisories are likely later today, and there are currently no other active winter alerts anywhere in the lower 48.

Peak Driving Danger Window

The worst will come from Wednesday night through Thursday morning across US-395, Tioga Pass, Sonora Pass, and Westgard Pass. NWS Reno notes the system will catch people off guard: "This temperature whiplash and the mountain snow chances tend to catch people with plans to recreate outdoors off-guard," the office wrote in its briefing graphic Sunday. The Weather Prediction Center has rated heavy snow risk HIGH for both Wednesday and Thursday, the only region in the lower 48 with that designation this week.

What To Expect

Snow totals (NWS Reno official): 4 to 8 inches across Mono County passes; around 2 inches at Mt. Rose Summit; less than 1 inch at other main Tahoe passes
Snow totals (WPC worst case): Up to ~14 inches at the highest Sierra crest above 10,000 feet in a low probability tail
Snow levels: Drop as low as 5,500 to 6,000 feet by early Wednesday morning, fluctuating 6,500 to 7,500 feet through Thursday, rising above 8,000 feet Thursday afternoon
Temperatures: Highs 15 to 20 degrees below late-May averages Wednesday and Thursday
Western Nevada high terrain: Light accumulating snow near the California border; valleys get rain showers and gusty winds
Worst corridors: US-395 along the Eastern Sierra, Tioga Pass (~9,945 ft), Sonora Pass (~9,624 ft), and Westgard Pass (~7,313 ft)

Western States In Play

NWS Reno's forecast covers both California's Eastern Sierra and most of western Nevada. The office expects new Winter Weather Advisories for Mono County above ~9,000 feet, with a Winter Storm Warning possible if totals trend toward the upper end of the range. Western Nevada will see Lake Wind Advisories already in effect through Wednesday morning, with light accumulating snow possible on the highest terrain near the California border. Beyond the Sierra footprint, including Oregon, Washington, Idaho, Montana, Wyoming, Utah, Colorado, New Mexico, and Arizona, there's no winter signal on the maps.

Road Conditions

Caltrans will likely require chains on most vehicles above 7,000 feet during the peak window, and AWD or 4WD with snow tires may still need them on the highest passes. If your vehicle isn't dialed in for mountain weather, Autoblog's roundup of the best cars and SUVs for snow and winter driving is worth a look. US-395 is the only paved north to south corridor along the Eastern Sierra, and any closure forces long detours. Tioga Pass typically just opens for the season in late May, and a late spring storm routinely re-closes it immediately after opening, stranding Yosemite high country travel plans.

Winter Driving Tips

California's chain control regulations apply through any active winter weather product. Carry chains, a blanket, flashlight, portable charger, water, food, and a full tank of fuel before crossing any pass. Autoblog's best practices for driving in snow, ice, and rain covers chain up technique, traction control settings, and what to do if you get stuck. Spring snow events change fast when air temperatures sit near freezing, so check Caltrans QuickMap before you leave and again at the base of any climb.

Timing

The cold front is already pushing through far northeast California and northwest Nevada Tuesday morning. Showers spread southward through the afternoon, with the heaviest precipitation Wednesday through Thursday, while the system tapers Thursday afternoon as the upper low lifts out and departs Friday. We'll update this article as the NWS issues formal winter alerts.