06/01/2026
Can One Winter Storm Paralyze I-80 Across the Sierra Nevada?
Interstate 80 through California’s Sierra Nevada, especially across Donner Summit, can transform from a vital mountain corridor into one of the most dangerous highways in the West when powerful winter storms strike. Heavy snowfall can blanket the roadway in a matter of hours, erasing lane markings and reducing visibility to near zero as icy pavement forms beneath a fresh layer of snow.
Strong winds often whip loose snow across the highway, creating sudden whiteout conditions that leave drivers unable to see vehicles ahead, stalled traffic, or abrupt slowdowns. In these moments, even experienced mountain drivers can lose control, and what begins as cautious travel can escalate into chaos within seconds.
During the worst snow events, traffic on I-80 frequently comes to a standstill. Spin-outs, jackknifed semi-trucks, and disabled vehicles block lanes as chain controls are enforced and some trucks are barred entirely. Despite snowplows operating around the clock, the relentless mix of snowfall, blowing snow, and freezing temperatures makes it nearly impossible to keep the highway fully clear, forcing long delays and occasional full closures for safety.
The rugged Sierra terrain only intensifies the danger. Steep grades, sharp curves, and high elevations allow snow and ice to build rapidly, while conditions can change without warning. Clear roads at lower elevations can give way to blizzard-like conditions near the summit, catching travelers unprepared.
Authorities repeatedly urge motorists to monitor road conditions closely, carry chains, and avoid unnecessary travel during major storms. On I-80 through the Sierra Nevada, winter can turn a scenic mountain drive into a high-risk gauntlet where a single storm decides who moves—and who doesn’t.