A powerful atmospheric river storm is sweeping across California, bringing significant flood and landslide risks to southern counties this weekend. Evacuation warnings have been issued as communities brace for potentially the wettest conditions in decades.
Impending Deluge and Evacuation Warnings
The National Weather Service predicts up to 5 inches of rain could fall within 48 hours across parts of southern California. Downtown Los Angeles may experience its wettest November since the 1980s. Authorities have issued evacuation warnings for neighbourhoods near recent wildfire burn scars, where the risk of dangerous mudslides and debris flows is particularly high.
The storm system, known as an atmospheric river, carries immense moisture volumes that can rival the flow at the mouth of the Mississippi River. While these systems are vital for replenishing California's reservoirs and snowpack, they also bring destructive potential.
Timeline of the Storm Threat
The first surge of rainfall began battering northern and central California on Thursday evening. However, meteorologists express greatest concern about the second surge expected from Friday night into Saturday.
The National Weather Service in Los Angeles warned of "growing risk for significant impacts on Saturday including dangerous flooding, damaging debris flows and major road closures". Santa Barbara, Ventura and Los Angeles counties face the highest threats.
In preparation, authorities closed Topanga Canyon Boulevard on Thursday evening due to high debris flow risks. This mountain thoroughfare was heavily affected by the Palisades fire earlier this year.
Multiple Hazards and Safety Advice
Beyond flooding and mudslides, the storm brings additional dangers including:
- Potential tornado development
- Damaging winds
- Heavy snowfall with up to a foot expected in the Sierra Nevada
- Up to 18 inches of snow on the highest peaks
The National Weather Service advised residents: "Saturday would be a great day to plan indoor activities & avoid traveling if possible to stay safe". While the San Francisco Bay Area has seen the worst pass, with wind gusts reaching 80mph in Marin County, southern California now faces the storm's full force.
Officials urge residents to monitor local updates and heed evacuation warnings, particularly those living near recent wildfire zones where ground conditions increase landslide risks.
