Heavy Rain and Flood Risk Expected Across Southern California From December 31 to January 2
CALIFORNIA — Southern California is facing increasing flood risk beginning Wednesday as a new storm system moves into the region, bringing heavy rain and the potential for debris flows and mudslides. Forecasters warn that conditions will worsen through Thursday and Friday as moisture continues to push inland.
The threat follows a period in which Santa Ana winds are expected to relax on Tuesday, briefly improving conditions before the stronger storm arrives. Rainfall between 2 and 5 inches is possible, with the heaviest amounts targeting southwest-facing slopes.
Storm Expected to Renew Flood and Mudslide Concerns
The incoming system is set to impact areas including Los Angeles, Santa Barbara, Santa Clarita, Oxnard, Irvine, and San Diego. Regions highlighted in the forecast map show both “flooding possible” and “flooding likely,” depending on local terrain and intensity of rainfall.
Southwest-facing slopes are expected to receive the highest totals, increasing the risk of runoff and debris flows. These areas are historically vulnerable when several inches of rain fall over a short period, especially following dry or windy conditions.
Timing and Impacts Through New Year’s Eve
Rain begins to increase on Wednesday as the system reaches California and the broader Southwest. Forecasters expect the heaviest and most widespread rainfall from Wednesday afternoon through Friday morning, aligning with New Year’s Eve and the start of the holiday weekend.
Communities in and around Los Angeles and the central coast may experience rapid rises in small streams, road flooding, and reduced visibility. Mudslide risk may develop in canyon or burn-scar areas, where unstable ground becomes saturated quickly.
Residents Urged to Monitor Conditions Closely
With 2–5 inches of rain projected between December 31 and January 2, emergency managers advise residents to stay alert to possible flood advisories or warnings. Drivers should use caution on mountain passes and coastal routes where water may pool quickly.
Southern California will remain under an elevated flood threat until the system begins to exit late Friday. For continuing updates and weather coverage, stay connected with NapervilleLocal.com.
I’ve lived in Naperville long enough to see how quickly our community changes — from new developments downtown to sudden shifts in our Midwest weather. Reporting on Naperville news and daily forecasts gives me the chance to keep neighbors informed about what really matters. My goal is simple: deliver clear, timely updates so you always know what’s happening in our city and what to expect from the skies above.