A potent storm system fueled by a strong atmospheric river is battering California, triggering a widespread flash flood warning and raising alarms across Southern California, the Bay Area, and parts of Northern California.
Forecasters warn that a dangerous scenario is unfolding, with life-threatening flooding, debris flows, heavy mountain snow, and damaging winds expected as the storm sweeps across the state.
Floodwaters have already surrounded homes in parts of Redding, while emergency officials issued evacuation orders in multiple counties as rainfall intensified early Wednesday.
Southern California Weather: Flooding Threat Intensifies
The most serious impacts are focused on Southern California, where the Weather Prediction Center (WPC) issued a rare Level 4 of 4 high risk flooding outlook for Wednesday. The alert covers more than 7 million people across Los Angeles, Ventura, Santa Barbara, and San Bernardino counties.
This is a dangerous and rapidly evolving situation, forecasters said, noting that flash flooding and debris flows are likely, especially near areas recently burned by wildfires.
Rainfall rates may exceed 1 inch per hour, enough to overwhelm storm drains and trigger fast-moving mudslides on burn scars from the Eaton and Palisades fires. These scorched areas repel water, turning heavy rain into torrents of mud, rocks, and debris.
California Weather: Atmospheric River Brings Multi-Day Threat
This storm is only the first of two atmospheric river systems expected to impact California weather through the end of the week. A second storm is forecast to arrive on Christmas Day, extending flooding concerns into Friday.
By week’s end, Southern California could see:
- 4 to 7 inches of rain in coastal and valley areas
- 6 to 14 inches in foothills and mountains
For perspective, parts of Los Angeles may receive two to six months worth of rain in just one week.
Bay Area Weather: Hurricane-Force Wind Gusts, Power Outages
Conditions are also deteriorating in Northern California, including the Bay Area, where wind gusts up to 108 mph were recorded in the northern hills early Wednesday.
Heavy rain and strong winds knocked out power to nearly 120,000 homes and businesses statewide, according to PowerOutage.us. Downed trees, flooded roads, and travel disruptions were reported across multiple counties.
Residents are urged to avoid unnecessary travel as additional rain bands move through.
Weather San Francisco: Severe Weather, Flood Risk Rising
In weather San Francisco forecasts, meteorologists warn of continued heavy rain and strong winds through Thursday. Urban flooding is possible, particularly in low-lying neighborhoods and areas with poor drainage.
Thunderstorms may also develop along the coast, bringing the risk of damaging wind gusts and even a brief tornado—a rare but possible scenario in California.
Evacuations Ordered Near Burn Scars
Evacuation warnings or orders have been issued in at least five Southern California counties, especially near wildfire burn scars.
Los Angeles County officials said deputies went door-to-door to notify residents in high-risk areas. Despite the warnings, some residents have chosen not to evacuate.
I would ask you to seriously reconsider, Los Angeles Police Chief Jim McDonnell said Tuesday, emphasizing the unpredictability of debris flows.
Mountain Travel Nearly Impossible
In the Sierra Nevada, feet of snow are falling, making travel dangerous or impossible along major routes, including Interstate 80 through Donner Pass.
The snow comes as a dramatic shift for the region, which had seen a slow start to the winter season.
Safety Reminders During a Flash Flood Warning
Officials urge residents to take flood warnings seriously:
- Never drive through flooded roads
- Avoid burn scar areas during heavy rain
- Prepare to move to higher ground quickly
- Monitor local alerts from the National Weather Service
Even six inches of moving water can knock an adult off their feet, while two feet can sweep away vehicles.
Outlook: Some Relief Ahead
After days of relentless storms, forecasters say some relief may arrive over the weekend, bringing a temporary break from the rain. Until then, Californians are urged to remain vigilant as this powerful storm system continues to impact the state.
