Redding, CA – Northern California is preparing for a prolonged period of hazardous weather as forecasters warn of heavy rain, flooding concerns, strong winds, and significant mountain snowfall from December 20 through early January. A briefing from the NOAA Climate Prediction Center indicates that a strengthening Pacific storm track will send multiple atmospheric rivers toward the region just ahead of Christmas.
What’s Driving the Incoming Storms
Meteorologists say a series of moisture-rich systems over the Pacific Ocean will begin impacting the region around December 20, with atmospheric river activity expected to intensify by December 22. These narrow corridors of concentrated moisture are known for producing prolonged heavy rainfall and have been linked to some of California’s most damaging winter floods in recent years.
According to NOAA forecasters, there is a moderate probability of heavy precipitation, estimated between 40 and 60 percent, during the peak window from December 22 through December 26. The area of greatest concern stretches from Northern California counties southward through west-central California, with some models indicating spillover effects reaching parts of Southern California later in the period.
Flooding and Landslide Concerns Increase
Officials warn that the flooding risk is elevated due to already saturated soils across portions of the Sacramento Valley, Northern Coast Ranges, and nearby foothills. Additional rainfall falling on wet ground could quickly overwhelm drainage systems, leading to river rises, urban flooding, and water pooling in low-lying areas.
Steep terrain poses another risk. Mudslides and debris flows are possible, particularly near recent burn scars, where vegetation that normally stabilizes hillsides is absent. Emergency managers often see rapid slope failures during atmospheric river events, sometimes with little warning.
Strong Winds and Coastal Impacts Expected
In addition to heavy rain, the storm pattern is expected to bring periods of strong onshore winds. Gusts could be most pronounced along the North Coast, exposed coastal headlands, and high mountain ridges, where downed trees and power outages become more likely.
Marine conditions are also expected to deteriorate, with rough seas and hazardous conditions for small craft during peak storm periods.
Sierra Nevada Snow May Disrupt Holiday Travel
While lower elevations deal with rain and flooding threats, the Sierra Nevada is forecast to receive moderate to heavy snowfall at higher elevations between December 20 and December 26. Snow accumulation could be significant over mountain passes, complicating holiday travel along major routes such as Interstate 80, U.S. Highway 50, and State Route 89.
Caltrans and emergency officials often urge travelers to carry chains, monitor road conditions closely, and be prepared for sudden closures during winter storm warnings.
La Niña Keeps Storm Door Open Into January
Climate experts say the persistent storminess is being reinforced by La Niña conditions in the Pacific Ocean. La Niña winters frequently steer wetter-than-average weather toward Northern California, increasing the likelihood of repeated storm waves rather than a single isolated event.
NOAA outlooks suggest that elevated precipitation chances may continue into early January, meaning communities could face multiple rounds of rain, wind, and snow as the new year begins.
What Residents Should Do Now
Emergency officials urge residents to stay alert and prepared as conditions evolve. Monitoring updates from National Weather Service offices in the Bay Area, Sacramento, and Eureka will be critical, as flood watches, wind advisories, and winter storm warnings may be issued with little lead time.
Basic preparedness steps include clearing storm drains, avoiding flooded roadways, securing outdoor items, and planning travel around forecasted impacts.
As Northern California heads into the heart of the winter storm season, forecasters emphasize that flexibility and early awareness will be key to staying safe during this extended period of unsettled weather.
Share your experiences in the comments below.