A powerful atmospheric river storm has unleashed life-threatening flooding across California on Christmas Day, December 25, 2025, prompting Governor Gavin Newsom to declare a state of emergency. The National Weather Service’s Weather Prediction Center (WPC) and AccuWeather have issued severe warnings for widespread weather hazards across the United States, with Southern California facing the most significant threat through Saturday, December 27.
Atmospheric River Brings Historic Rainfall and Flooding
According to meteorologists, a strengthening storm off the West Coast is driving a potent atmospheric river into California. This weather system is bringing catastrophic conditions, including life-threatening flooding, mudslides, hurricane-force winds, and several feet of mountain snow. AccuWeather warns that Southern California is at the highest risk, where multiple inches of rain could fall in just a few hours across urban zones and steep terrain.
Coastal areas of Southern California are expected to receive several months' worth of rainfall in just one to three days. The downtown Los Angeles area is projected to receive 4–8 inches of rain, which is two to three times the region's average for the entire month of December, stated AccuWeather Senior Meteorologist Tyler Roys.
The WPC has issued a Moderate Risk (Level 3 of 4) of excessive rainfall for parts of Southern California from Thursday into early Friday. The agency warns of numerous flash flooding events, along with dangerous stream and river flooding. Areas near recent wildfire burn scars are at particular risk of destructive debris flows.
State of Emergency and Evacuations Ordered
The escalating crisis has led to states of emergency being declared in several counties, including Los Angeles, Orange, Riverside, San Bernardino, San Diego, and Shasta. In response to the mounting flood fears, evacuation orders have been issued for residents living near burn scar areas in Los Angeles County, forcing some to leave their homes on Christmas Day.
In Shasta County, which includes the city of Redding, officials are preparing for renewed flooding after a recent deadly event. Governor Gavin Newsom emphasized the state's proactive measures, stating, "California is acting early and decisively to do all we can to get ahead of dangerous winter storms. The state has pre-positioned resources, activated emergency authorities, and we are working closely with local partners to protect communities and keep Californians safe."
Widespread Winter Hazards Across the United States
The severe weather is not confined to California. The WPC forecasts multiple hazards across the nation from December 25 to 27. In the West, heavy snow is expected in the Sierra Nevada Mountains through Saturday, with AccuWeather Chief Meteorologist Jonathan Porter predicting historic totals of 8–12 feet on many ridges and peaks, with isolated amounts reaching up to 15 feet. Significant snowfall is also forecast for the Cascades and the Northern and Central Rockies.
In the eastern United States, a separate weather system is creating hazardous conditions. A low-pressure system moving from the Ohio Valley to the Northeast Coast is bringing rain and snow, while a second storm from the Upper Midwest is spreading a wintry mix of freezing rain and sleet from Michigan through Pennsylvania and into the Mid-Atlantic. The WPC notes that up to 0.25 inches of ice accumulation is possible in parts of Pennsylvania, creating extremely dangerous travel conditions. Moderate to heavy snow is also likely over New England from Friday into Saturday.
As California battles this Christmas Day deluge, the focus remains on emergency response and public safety, with officials urging residents in high-risk areas to heed all evacuation orders and warnings immediately.
