California Faces Major Flood and Mudslide Threat as Christmas Storm Targets Los Angeles With 10–20 Inches of Rain
LOS ANGELES, CALIFORNIA — A powerful late-December storm system is taking aim at Southern California, with forecasters warning that parts of the Los Angeles region could see extreme rainfall totals between December 22 and December 26, raising serious concerns about flooding, debris flows, and dangerous mudslides just days before Christmas.
Forecast models show the most significant impacts focused across Los Angeles County, Ventura County, Santa Barbara County, and Riverside County, where saturated soils and recent burn scars create a heightened risk for life-threatening conditions.
Day 4 Excessive Rainfall Outlook Shows Elevated Flood Risk
The Day 4 Excessive Rainfall Outlook places much of Southern California under a Moderate Risk (Level 3 of 4) for excessive rainfall, a designation that signals a high likelihood of flooding impacts.
The risk zone stretches from Santa Barbara and Oxnard through Los Angeles and Long Beach, extending inland toward Riverside and the foothill communities near Santa Clarita and Palmdale. Surrounding areas, including desert communities such as Victorville, remain under a Slight Risk, indicating heavy rain is still possible outside the core impact zone.
Meteorologists note that moderate-risk designations this far out in the forecast are uncommon, underscoring growing confidence that this storm will deliver widespread and impactful rainfall.
Forecast Totals Show 10–20 Inches Possible in Hills and Mountains
Rainfall projections for the five-day period from December 22 to December 26 show staggering totals across the region. Coastal and valley locations, including much of Los Angeles, are expected to receive 5 to 8 inches of rain, while surrounding hills and mountains could accumulate 10 to 20 inches, particularly along south-facing slopes.
The highest totals are forecast in the Santa Monica Mountains, San Gabriel Mountains, and Transverse Ranges, where orographic lift enhances rainfall as moist Pacific air is forced upward. Offshore moisture plumes feeding into the system further amplify precipitation rates.
If these projections verify, Los Angeles could receive nearly 90 percent of its average annual rainfall before the end of the year, a remarkable statistic that highlights the intensity of this single weather event.
Burn Scars Create High Mudslide and Debris Flow Danger
One of the most alarming aspects of this storm is its timing and interaction with recent wildfire burn scars, which dramatically increase the risk of flash flooding and debris flows.
Officials are particularly concerned about the Eaton Fire burn scar, where vegetation loss has left slopes unstable. Even brief periods of intense rainfall could trigger rapid mudslides, rockfalls, and debris flows, threatening nearby neighborhoods, roadways, and evacuation routes.
Historically, similar setups in Southern California have led to sudden and destructive mudslides, sometimes occurring within minutes of heavy rainfall onset. Emergency managers are urging residents in burn scar zones to remain alert and prepared for possible evacuation orders.
Christmas Eve and Christmas Day May Bring Peak Impacts
While rain is expected to begin earlier in the forecast window, Christmas Eve and Christmas Day appear most likely to bring the heaviest precipitation and strongest impacts.
During this period, rainfall rates may intensify, overwhelming urban drainage systems and causing street flooding, freeway closures, and dangerous travel conditions across the Los Angeles metro area. Coastal communities could also see minor flooding, while inland areas face swollen creeks and rapidly rising rivers.
Forecasters caution that the Moderate Risk could still be upgraded to a High Risk if confidence increases in extreme rainfall rates over a concentrated area, a scenario that would indicate an even greater threat to life and property.
What Residents Should Prepare for Across Southern California
Emergency officials recommend that residents across Southern California take this storm seriously and prepare ahead of time, especially those in flood-prone or burn scar areas.
Key concerns include:
- Flash flooding in urban areas
- Mudslides and debris flows near burn scars
- Road closures and travel disruptions
- Power outages from saturated soils and falling trees
- Dangerous coastal and mountain travel conditions
Residents are urged to monitor local forecasts, avoid driving through flooded roads, and follow any evacuation guidance issued by local authorities.
As California braces for one of its most impactful storms of the season, the days leading up to Christmas may test infrastructure, emergency response systems, and public readiness across the Los Angeles region. For continued coverage on severe weather, storm impacts, and regional updates, visit ChicagoMusicGuide.com.