Snow is piling up across Southern California’s mountain passes and wind gusts are hitting 45 mph, forcing hazardous driving conditions on some of the region’s most-traveled routes. The National Weather Service’s Los Angeles/Oxnard forecast office issued a Winter Weather Advisory on Saturday, April 25, 2026, covering the Interstate 5 corridor, the western and eastern San Gabriel Mountains, and the interior mountains of Santa Barbara and Ventura counties. The advisory runs through Monday morning, April 27, and warns that snow levels will plunge from roughly 7,000 feet to 4,500 feet, dragging wintry conditions down to elevations where commuters and weekend travelers regularly drive.
Why the snow-level drop matters
At 7,000 feet, snow stays on the highest ridgelines and rarely disrupts traffic. At 4,500 feet, the picture changes fast. That elevation sits squarely in the range where Interstate 5 crosses the Tejon Pass near Gorman and Frazier Park, and where State Route 2 winds through the San Gabriel Mountains above La Canada Flintridge. Both corridors are major commuter and freight routes, and both become treacherous when snow and ice coat the pavement.
The NWS advisory is paired with a simultaneous Wind Advisory for the same zones. Gusts reaching 45 mph can turn fresh snowfall into blowing whiteouts, especially on exposed stretches above the tree line in the San Gabriels and along the open ridges of the I-5 corridor. Drifting snow on roadways compounds the danger, reducing lane visibility to near zero in the worst bursts.
Chain controls and what drivers need to know
When conditions deteriorate on California mountain highways, Caltrans activates chain controls at checkpoints below the snow line. Under state law, drivers entering a chain-control zone must carry and, when directed, install tire chains or approved traction devices. Vehicles without the correct equipment can be turned back or cited, and all-wheel drive does not automatically exempt a vehicle from every control level.
Whether chain controls are currently active on I-5 through the Grapevine or on SR-2 in the Angeles National Forest depends on real-time conditions that shift quickly during an active storm. The most reliable way to check is the Caltrans QuickMap tool, which publishes live road-condition data for Los Angeles, San Bernardino, Ventura, and Santa Barbara counties. The California Highway Patrol also advises travelers to verify conditions shortly before departure rather than relying on a forecast checked hours earlier…