California – A powerful atmospheric river is expected to bring extreme snowfall, dangerous flooding, and high winds across California through Friday.
According to the Weather Prediction Center and the National Weather Service, this multi-day event will deliver widespread heavy rain at lower elevations and prolonged, intense snowfall in the Sierra Nevada. In the highest elevations, particularly along the Sierra crest, storm-total snowfall could exceed 200 inches, with Winter Storm Severity Index ratings reaching major to extreme levels.
Forecasters indicate the heaviest precipitation will occur from Tuesday night through Wednesday, with additional rounds continuing through Friday as the atmospheric river stalls over the state. Excessive Rainfall Outlooks place portions of central and southern California, including the greater Los Angeles area, under moderate to high risk for flash flooding. Urban flooding, debris flows, landslides, and rockfalls are likely, especially in burn scar areas and steep terrain.
In the Sierra Nevada, snow levels will initially remain high before lowering, leading to a prolonged period of heavy, wet snow at higher elevations. Locations near Mammoth Mountain, Tioga Pass, and the John Muir Trail corridor show extreme snowfall potential, with multiple feet likely and isolated totals exceeding 200 inches in worst-case scenarios. Snow load impacts, whiteout conditions, and extended road closures are expected.
Strong winds will accompany the system through Thursday, particularly in mountain and coastal areas. Tree damage, power outages, and hazardous travel for high-profile vehicles are likely.
Officials warn that travel through the Sierra may become difficult to impossible, and residents in flood-prone areas should be prepared for rapidly changing conditions.
This event poses significant risks for commuters, holiday travelers, mountain communities, and emergency responders across California.
Residents are urged to closely monitor official forecasts, heed evacuation or travel advisories, and avoid unnecessary travel in impacted regions.
