Southern California is bracing for a holiday storm of rare intensity, with meteorologists and public officials warning of life-threatening flooding, mudslides, and travel chaos as millions of residents and travelers prepare for Christmas Eve and the days that follow. According to the National Weather Service (NWS), an exceptionally strong atmospheric river—sometimes called a "pineapple express"—is set to unleash heavy rain, fierce winds, and hazardous conditions across the region starting Tuesday night, December 24, 2025.
For many, the timing couldn’t be worse. AAA predicts that a record 10.2 million people in Southern California will travel at least 50 miles from home during the holiday period, with more than 8 million Americans expected to fly nationwide on Tuesday alone. Close to a million of those flyers will depart from Southern California airports, as reported by ABC7. But with a storm system barreling in from the Pacific, both air and road travel face significant disruptions. "We already missed our flight," one frustrated traveler told Eyewitness News. "We arrived too late. We missed the check-in time, so we were supposed to come two hours ahead of time and we didn’t at all. So we missed the cut off time to check our bags, and now I’m on hold with United to see if we can book another flight."
Others managed to dodge the worst of the pre-storm rush. "I’ll be honest, it wasn’t so bad," said Rebecca Hedwat. "Honestly! We travel every year around this time, and this is probably the best for me. We left also super early." The lesson? Leave early and expect delays, especially as the storm makes landfall and traffic snarls build.
The storm’s first wave is expected to hit Santa Barbara around 9 p.m. Tuesday before moving to Los Angeles around midnight, with heavy rain likely to continue for up to 18 hours—possibly until 6 p.m. Wednesday. Rainfall rates may exceed one inch per hour at times, particularly in higher elevations. Overall, widespread totals of 3 to 7 inches are forecast, with some localized areas potentially receiving as much as 9 inches or more, according to ABC News. For context, the region typically sees just 2 to 3 inches of rain in the entire month of December.
The NWS Weather Prediction Center has issued a rare "High Risk" (level 4 of 4) for excessive rainfall and flash flooding across portions of Southern California, including Santa Barbara, Ventura, Los Angeles, and San Bernardino counties. This designation is only issued about 4% of days and accounts for a disproportionate share of flood-related fatalities and damages. Cities like Los Angeles, Burbank, Glendale, San Bernardino, Santa Clarita, and Thousand Oaks fall within this high-risk zone.
Evacuation warnings and orders are already in effect for nearly 400 properties in recent wildfire burn scar areas of L.A. County, starting at 11 a.m. Tuesday. The Palisades, Sunset, and Hurst burn scar regions are under particular scrutiny, with law enforcement going door-to-door to alert residents. "Those recommendations are based on technical science, forecasting of the current weather event and our best estimate for who would be most vulnerable," Mark Pestrella, director of the L.A. County Department of Public Works, told LAist. If residents weren’t home, officials left flyers and promised to revisit to ensure everyone got the message.
Recent wildfire burn scars dramatically increase the risk of flash flooding and debris flows. The NWS warns that in these areas, even half an inch of rain in less than an hour can trigger dangerous floods and mudslides. Burned soil can become as water-repellent as pavement, sending rainfall rushing downhill instead of soaking into the ground. The risk is greatest in the first two years after a fire, and with Southern California recently experiencing both severe drought and periods of heavy rain—what scientists call "hydroclimate whiplash"—the landscape is primed for disaster.
"With as much total rain as what we’re expecting, widespread, significant flooding will likely occur in urban and poor drainage areas, especially in and around the higher terrain," said Ariel Cohen, Meteorologist-In-Charge at the NWS in Oxnard, during a press conference. "There will almost certainly be numerous rock slides and mudslides, along with areas of severe flooding in urban locations and along freeways, which is why being out on the roads will be exceptionally dangerous."
Travelers are being urged to check conditions before heading out. Road closures have already been announced for Malibu Canyon, Tuna Canyon, Chantry Flat, and Glendora Mountain roads. The NWS has placed much of Southwest California under a flood watch from 4 p.m. Tuesday through at least Thursday night, with the heaviest rain expected to peak on Christmas Eve. While a brief lull in precipitation is possible Wednesday afternoon, forecasters caution that rain will likely resume Wednesday night and persist into Christmas Day and beyond.
Wind is another major concern. Gusts of 35 to 55 mph are likely in coastal and valley areas of L.A. County, with higher elevations potentially seeing gusts up to 60–70 mph. Wind advisories extend up and down the coast, with the possibility of isolated gusts exceeding 70 mph in the mountains. These winds could bring down trees and power lines, leading to outages and further hazards. There’s even a "small chance for a brief, weak tornado," the NWS noted.
L.A. Mayor Karen Bass has urged residents to complete any necessary travel before the rain intensifies Tuesday evening. "Staying off the roads whenever possible keeps you safe and frees up the lanes for our first responders and public works crews," Bass said. National Weather Service meteorologist Kristan Lund also advised caution, warning that even after a temporary break in the rain, conditions could rapidly deteriorate again. "We encourage people to be aware that it will take less and less rain as we go through the week for more and more impacts to happen," Lund said. "Just because one canyon doesn’t have rock slides tonight, it might end up having rock slides in the next impulse."
Officials are emphasizing the importance of taking flood warnings seriously and preparing for power outages, swiftwater rescues, and prolonged disruptions. Residents are advised to have emergency supplies ready, avoid driving through standing water, and check on neighbors—especially those in vulnerable areas. The National Weather Service and local agencies are providing regular updates, and resources such as sandbags are available at local fire stations.
As the region faces a storm that meteorologists say only occurs once every five to ten years, the message from authorities is clear: stay informed, stay prepared, and—if at all possible—stay home. The combination of heavy rains, strong winds, and holiday travel could make for a dangerous mix, but with caution and planning, Southern Californians can weather the storm together.
