Heavy rain and wind gusts as high as 80 miles (129 kilometers) per hour lashed the region, upending travel and leading to at least one death in San Mateo County, south of San Francisco. A flood advisory is in effect in the Bay Area throughout the morning, the National Weather Service's local office said on Twitter.

The low-pressure system will gradually weaken Wednesday, however its outer edges will ripple through the Southwest and into the Rockies, the weather service said in a statement. "Dangerous to difficult travel is likely" there, with as much as 2 feet (0.6 meters) of additional snowfall expected in mountain areas.

San Francisco International Airport saw flight delays early Wednesday. About 137,000 homes and businesses across the state remained without electricity by 3 a.m. local time, according to the website PowerOutage.us. On Tuesday, a train between Oakland and Sacramento derailed after contact with a tree, shutting service just before the evening commute.

"This was a violent, sudden windstorm," said Daniel Swain, a climate scientist at the University of California at Los Angeles. "We're seeing impacts probably that are similar to a strong tropical storm or a weak hurricane."