Strong atmospheric river brings heavy rainfall and flooding across Southern California over Christmas
A major atmospheric river swept across Southern California from late December 24, 2025, into Christmas Day, December 25, triggering widespread flash floods, evacuations, debris flows, and power outages. Multiple counties including Los Angeles and Ventura were put under a State of Emergency. Rainfall totals reached 75–150 mm (3–6 inches) in coastal and valley areas, with up to 250 mm (10 inches) in higher terrain of Los Angeles and Ventura counties, prompting officials to urge residents to avoid travel.
Mudslide closed Topanga Canyon Boulevard (SR-27) from PCH to Grand View Drive on Dec. 24, 2025. Image credit: Caltransdist7
A major atmospheric river swept across Southern California on December 24–25, flooding roads, prompting evacuations, and disrupting holiday travel.
Over 150 mm (6 inches) of rainfall was recorded in mountainous areas of Los Angeles and Ventura counties. Flash flooding, debris flows, and power outages affected multiple communities as officials urged residents to avoid travel until conditions improved.
This atmospheric river produced sustained rainfall from late December 24 into Christmas Day, with rates locally exceeding 25 mm (1 inch) per hour. Coastal and valley areas received around 75–150 mm (3–6 inches), while higher terrain recorded up to 250 mm (10 inches).
Soils across much of the region were already saturated due to multiple atmospheric rivers impacting the U.S. West Coast since early this month.
Flash Flood Warnings and High Wind Warnings were issued across Los Angeles, Ventura, Santa Barbara, and San Diego counties. Gusts reached 65–95 km/h (40–60 mph) in exposed coastal and foothill locations, downing trees and power lines.
Over 30 000 customers reported power outages at the peak of the storm in Los Angeles and Ventura counties. Burn scar zones, including areas affected by the 2022 Woolsey and 2023 Eaton fires, were struck by mudslides that blocked roads and damaged property.
Governor Gavin Newsom declared a State of Emergency in Los Angeles, Orange, Riverside, San Bernardino, San Diego, and Shasta counties.
“A series of atmospheric rivers has brought high-intensity rainfall and strong winds statewide to already saturated soils, heightening the risk of flooding, landslides, debris flows, and rapidly rising creeks and rivers. Recently burned areas in Southern California, including the Airport, Bridge, Line, Palisades, and Eaton Fire burn scars, face an increased threat of mudslides and debris flows as heavy rain continues,” the governor said.
Fifty-five fire engines, 10 swift water rescue teams, five hand crews, five dozers, four loaders, three helicopters, an incident management team, an Urban Search and Rescue Team, and over 300 personnel were pre-deployed to protect communities and support local response efforts.
Emergency crews across Southern California carried out multiple water rescues overnight as fast-rising runoff inundated low-lying neighborhoods.
In Los Angeles County, fire officials responded to stranded motorists on the 101 Freeway near Studio City and closed several sections of Mulholland Drive due to slope instability. Evacuation warnings were issued for portions of Malibu, Topanga Canyon, and the Santa Barbara foothills, where rainfall intensity reached critical thresholds for debris flows.
The storm caused significant travel disruptions during the Christmas holiday period. Portions of I-5 north of Los Angeles were temporarily closed due to flooding and snow accumulation at higher elevations near Tejon Pass.
The San Bernardino County Sheriff’s Department issued an Evacuation Order for the communities north of Highway 2 to Palmdale Road west of Sheep Creek Road to the Los Angeles County line.
An Evacuation warning was issued for Wrightwood earlier in the day but elevated the advisory to a shelter-in-place order as flood conditions worsened. The Angeles Crest Highway, a major traffic route through the San Gabriel Mountains, was closed in two stretches due to flooding, reported Reuters.
Rainfall monitoring data indicated that downtown Los Angeles received approximately 110 mm (4.3 inches) of rain within 24 hours between December 24 and 25. Snowfall was forecast above 2 100 m (7 000 feet), potentially creating additional hazards for mountain travelers, with heavy precipitation continuing into December 26.
Read more:
I am an Assistant Editor and Severe Weather & Science Journalist at The Watchers, specializing in real-time severe weather coverage, geophysical event reporting, and research-driven scientific analysis. You can reach me at rishav(at)watchers(.)news.
Where’s El Presidente?