A gale warning and severe thunderstorm threats put the Los Angeles-area coastline on alert Monday as a powerful winter storm system began lashing California with heavy rain, high winds and the potential for dangerous flooding and debris flows.
The National Weather Service issued a gale warning through 2 a.m. Tuesday for inner waters from Point Mugu to San Mateo Point, including Santa Catalina and Anacapa islands, with southwest winds of 20 to 30 knots, gusts up to 35 knots and combined seas of 6 to 9 feet. Forecasters warned the conditions could capsize or damage vessels and urged mariners to remain in port or seek safe harbor.
A special marine warning was also issued Monday for the same waters after severe thunderstorms capable of producing waterspouts were detected on radar moving east at 30 knots, with wind gusts exceeding 50 knots. Locations impacted included Dana Point, Newport Harbor, Alamitos Bay and the Port of Los Angeles.
Los Angeles area residents in neighborhoods scarred by last year's devastating wildfires were placed under an evacuation warning through Tuesday because of the potential for mud and debris flows. Mayor Karen Bass said she ordered emergency crews and city departments to be ready to respond to any problems.
The Weather Prediction Center issued a slight risk of excessive rainfall for the central and southern California coast through Tuesday morning, warning that heavy rain could create localized flash flooding, with urban areas, roads, small streams and burn scars the most vulnerable.
Forecasters said a deep upper-level trough moving across the state could dump up to 8 feet of snow on the western slope of the Sierra Nevada, northern Shasta County — including portions of Interstate 5 — and parts of the Coast Range before the storm moves through late Wednesday. Chains were required on vehicles navigating Sierra Nevada roadways as of Monday.
A second front was expected to move onshore over the West Coast on Tuesday evening, producing additional rain at lower elevations and snow at higher elevations.
"It has seemed 'spring-like' for a large part of 2026, but winter is set to show it's not quite done yet," the Shasta County Sheriff's Office said in a social media post urging residents to stay aware of the storm.
Pacific Gas & Electric said it was using artificial intelligence and machine-learning enhanced weather models to determine where to send crews and equipment ahead of the storm. The utility said the weather event will "progress in several phases," with multiple storm systems moving through the region that will likely intensify risks from wind, rain and snow.
California's Office of Emergency Services said it is placing fire and rescue personnel and resources in areas most at risk for flooding, mud and debris flows.
Rain had already begun Sunday in the San Francisco Bay Area, prompting flood warnings. In coastal Santa Barbara County, a large eucalyptus tree fell across the 101 Freeway, shutting the southbound side to traffic.
In the mountain community of Wrightwood, about 80 miles northeast of Los Angeles, resident Kashawna McInerny spent Monday trenching her side yard to direct stormwater away from her home and placing barriers to keep mud and debris from overtaking her laundry room. McInerny said she still has several tons of rock and debris on her property from storms over the Christmas and New Year holidays.
"We're not panicking yet. At least I'm not," she said with a laugh.
Beyond California, parts of eastern Colorado were under fire danger warnings Monday due to abnormally high temperatures, gusty winds and dry conditions, with gusts up to 60 mph expected on the eastern plains Tuesday. Parts of Texas, New Mexico and Kansas were also under red flag warnings.
The storm system was expected to push eastward by midweek, bringing rain, snow and freezing rain to the Upper Midwest, Great Lakes and Northeast.
The Associated Press contributed to this report.