A powerful atmospheric river is set to impact Southern California, bringing several days of heavy rainfall starting Tuesday, with the most intense downpours expected on Wednesday. Officials have issued a flood watch for Los Angeles County, warning that rainfall rates could exceed one inch per hour, heightening the risk of mudslides and debris flows, particularly in areas that have recently faced wildfires. Alongside the rain, damaging winds are forecasted to continue through Christmas Day, while snow levels are expected to remain high at approximately 7,000 feet.
This weather event is characterized as a warm atmospheric river that will linger over the region for five consecutive days, delivering significant moisture. Forecasters predict that from Wednesday through Christmas Day morning, areas in the Los Angeles metro could experience flash flooding, rated at a Level 3 risk out of 5. Rainfall totals are projected to vary between 5 to 8 inches across coastal and valley regions, with higher amounts of 8 to 12 inches in foothill and mountainous areas.
In light of this impending storm, the city of Los Angeles has announced evacuation warnings for residents in Pacific Palisades and Mandeville Canyon, near the Palisades Fire burn area, due to concerns over potential debris flows. This warning is active from Tuesday at 11 a.m. until Thursday at 11 p.m. Officers from the Los Angeles Police Department will reach out to residents in high-risk zones.
The storm will initially bring light rain on Tuesday, but intense downpours will commence after midnight, with peak rainfall expected on Wednesday. Winds are anticipated to become very strong, with mountainous regions facing gusts up to 80 mph and lower areas experiencing 40 to 50 mph gusts. Rain rates are expected to intensify significantly, particularly in upslope areas, which may lead to urban flooding as storm drains become overwhelmed.
Local authorities, including the Los Angeles Fire Department and city personnel, are ramping up preparations to ensure public safety and to respond to potential emergencies related to swift-water rescues and debris flows. Mayor Karen Bass has encouraged residents to stay informed about the weather and heed safety precautions, particularly those living near burn scars.
As the storm approaches, residents are advised to take proactive measures such as clearing drains and gutters, securing outdoor items, and exercising caution while traveling, especially during periods of peak winds and rainfall. Although the storm poses several challenges, the community is coming together to enhance preparedness and resilience during this holiday season.