A powerful atmospheric river storm hit California on Wednesday, causing dangerous flooding, strong winds and heavy mountain snow. Evacuation orders and warnings were issued across multiple counties as the risk of flash flooding and debris flows increased. State and local officials have declared emergencies to support response efforts.
Atmospheric River Brings Heavy Rain and High Flood Risk
The National Weather Service reported that flooding rain and intense winds will continue across Northern and Southern California through Christmas Day. In addition, Flash Flood Warnings were issued for Santa Barbara, Ventura and San Mateo counties. Ventura County saw rain rates up to 0.60 inches in 30 minutes. Meanwhile, some mountain regions near Los Angeles have already received 4 to 8 inches of rain.
Millions remain under flood alerts, and as a result, areas with recent wildfire burn scars face the highest danger due to rapid runoff and debris flows. These scars shed water quickly, so flooding develops faster in these locations.
California Declares State of Emergency
California Gov. Gavin Newsom declared a state of emergency for Los Angeles, Orange, Riverside, San Bernardino, San Diego and Shasta counties. Furthermore, the order activates resources and emergency authorities to protect communities. The city of Los Angeles also declared a local emergency to ensure access to needed equipment and support.
A rare high-risk flood alert was issued for more than 7 million residents across Los Angeles, Ventura, San Bernardino and Santa Barbara counties. Although high-risk flood events are uncommon, they often lead to major damage and disruptions. Flash Flood Warnings continued through early Christmas Day.
Emergency crews carried out rescues in Wrightwood, a mountain resort community in the San Gabriel Mountains. Flooded cars, damaged homes and fast-moving water created hazardous conditions. In response, helicopters lifted residents from rooftops, and about 120 emergency personnel worked through the night. Highway 2 closed after heavy flooding and debris flows blocked access.
More Atmospheric River Impacts Expected Through Christmas
Forecasters warn that rain and high winds will continue through Christmas night and into Friday. Moreover, another atmospheric river system will arrive on Christmas Day, raising a Level 3 of 4 flood risk for more than 12 million people. These high-impact events cause most U.S. flood damage each year.
Rainfall rates may reach 1 inch per hour again, which can trigger rapid flash flooding and debris flows on burn scars such as the Eaton and Palisades fire areas.
Significant Rainfall Totals Expected Across Southern California
Southern California could receive 4 to 7 inches of rain in coastal and valley regions. Foothills and mountains may see 6 to 14 inches. Consequently, Los Angeles could experience several months’ worth of rainfall in only one week.
Strong winds will continue and may lead to more downed trees and power outages as the storm progresses.
