Southern California storm tracker: Pineapple Express to bring massive flooding, gusty winds through Christmas
Christmas storms arrive in Southern California
The earliest stages of the rain system have arrived in Southern California.
LOS ANGELES - Holiday travel plans are under threat as a powerful atmospheric river targets Southern California, bringing a week of relentless rain and damaging winds that could cause severe flooding and debris flows, especially recent burn scar areas.
UPDATE: Dangerous holiday storm heads to Southern California: Timeline
Multi-day atmospheric river
Big picture view:
Forecasters are warning of a very strong, subtropical weather system—an atmospheric river—that will stall over Southern California for five consecutive days.
This system is carrying "copious" amounts of moisture, leading to a high-impact weather event that will likely last from Tuesday through Saturday evening. Heavy clouds moved over Los Angeles Tuesday evening ahead of the storm, which forecasters say could disrupt Christmas travel across the region.
Unlike typical winter storms, this is a warm system, meaning heavy rain rather than snow will be the primary concern for most residents.
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According to the FOX Weather Center, the Los Angeles metro area is under a Level 3 out of 5 risk of flash flooding from Wednesday through Christmas Day morning, with up to 5 to 8 inches of rain possible. Wind gusts could reach up to 50 mph, increasing the risk of downed trees and power outages.
A flood watch will be in effect from Tuesday afternoon through Thursday evening for much of Los Angeles County, with mud and debris flows possible across foothill and mountain areas, including recent burn scars, according to the National Weather Service.
Evacuations
What we know:
The city of Los Angeles has issued an evacuation warning for residents of Pacific Palisades and Mandeville Canyon near the Palisades Fire burn area due to possible debris flows from an impending storm. The warning will be in effect from 11 a.m. Tuesday to 11 p.m. Thursday. Residents living in particularly high-risk areas will be visited by Los Angeles Police Department officers.
Additional evacuation orders and warnings are in place for hundreds of residents near recent wildfire burn scars across Southern California, where the risk of flash flooding and debris flows is highest.
The evacuations affect just over 300 homes, including 126 in unincorporated county areas, with the remaining homes located on city property. These homes are near hillsides and burn scars, where the risk of debris flows is highest. Law enforcement officers have been going door to door to advise residents of the evacuation warning. Some residents are choosing to leave, while others are staying.
"The idea is to take a surgical approach," officials said. "Instead of ordering an evacuation for an entire neighborhood, you concentrate on the homes that are most at risk."
Los Angeles Mayor Karen Bass urged residents to take the storm seriously, saying the city has mobilized additional resources in preparation.
"The city has positioned additional resources, including heavy-duty fire engines and swift-water rescue teams," Bass said.
Preparing residents ahead of CA storms
Law enforcement went door to door to check on families most vulnerable to the incoming Christmas storms.
Key impacts and hazards
What we know:
Beyond the rainfall, "very strong winds" will pose a threat Tuesday night and into Wednesday, according to the latest forecast.
Mountain peaks could see gusts up to 80 mph, while lower elevations may experience 40-50 mph winds, the NWS said.
Rainfall Totals: Widespread totals of 4–8 inches for coastal and valley areas, with 8–12+ inches expected in the foothills and mountains.
Damaging Winds: A High Wind Watch is in effect. Peak gusts could reach 80 mph in favored mountain passes and 40–60 mph across Santa Barbara, Ventura, and LA Counties.
Flood & Mudslide Risk: Hourly rain rates may exceed 1 inch per hour on Wednesday. This intensity is high enough to trigger mudslides, debris flows in burn areas, and severe urban flooding from clogged drains.
Officials warned that the number of affected homes could change if rainfall intensifies and urged residents to monitor the news and sign up for emergency alerts. A flood watch will be in effect from Tuesday afternoon through Thursday evening for much of Los Angeles County, with mud and debris flows possible across foothill and mountain areas, including recent burn scars, according to the National Weather Service.
National Weather Service officials warned that significant flooding is likely, particularly in urban areas, poor drainage locations and near higher terrain.
"This is a very dangerous storm," said Dr. Ariel Cohen of the National Weather Service. "Widespread significant flooding will likely occur, especially in and around higher terrain."
Officials are also closely monitoring mudslide-prone areas such as Mulholland Drive, which has a history of slope failures. Nearly two years ago, heavy rain triggered slides that left at least one home uninhabitable and forced long-term road closures.
Residents say the threat remains concerning.
"It’s especially worrying since it washed out Mulholland and closed it for many months for repairs," said one nearby resident.
Some residents are already questioning whether to proceed with holiday plans.
"We’ve got some family coming to town and they’re already asking, ‘Should we come up?’" said Los Angeles resident Justin Yovino. "I don’t know. Is there going to be flooding?"
Weather officials urged residents to avoid unnecessary travel during the holiday period.
"If you’re planning to be out on the roads during the Christmas holiday, please reconsider your plans," Cohen said.
Timeline of the storm
Timeline:
While Tuesday will start with light rain, intensity will spike after midnight, the NWS said.
Forecasters expect "upslope" areas and south-facing mountains to see the most significant impact, with rain rates capable of clogging storm drains and causing severe urban flooding. Residents in vulnerable areas are urged to take protective actions immediately.
The worst of the weather is slated for Wednesday, but periods of heavy rain will likely persist through Christmas Day, according to the latest forecast.
Wednesday: The Peak of the Storm. Extremely heavy rain and peak wind speeds will occur throughout the day.
Christmas Day (Thursday): A second "burst" of heavy rain and strong wind is now expected, potentially causing holiday travel disruptions.
Friday – Saturday: Rain tapers off to sporadic showers, with dry weather finally returning by Sunday.
What we don't know:
While mountain areas are almost certain to see 1"+ per hour rates, there is still some uncertainty regarding exactly how intense the rain will be in the lower elevations of Ventura and LA Counties.
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While not a "convective" storm by nature, isolated thunderstorms are possible Wednesday, which could locally double the rainfall intensity.
Be prepared, NWS warns
What they're saying:
"Hourly rain rates, especially in the upslope areas, should easily top one inch per hour during the peak of the storm on Wednesday," the NWS said. "The heaviest rain will be in the south-facing mountains, but very heavy rain, possibly close to an inch per hour, is possible at lower elevations as well and anyone in particularly vulnerable areas ... or any recent burn scars should start taking protective actions ASAP.
"There will almost certainly be numerous mudslides, severe flooding either from heavy rain or clogged storm drains, and possibly debris flows near recent burn scars," forecasters continued.
"Los Angeles city personnel are preparing for the storm this holiday week," Mayor Karen Bass said in a statement. "First responders, public works crews, and utility personnel are ready to respond to potential impacts due to the weather. Angelenos planning to travel to spend time with family and loved ones this holiday week should use caution on the roads, plan ahead, and stay informed. Sign up for emergency alerts at NotifyLA.org."
When will the rain end?
What's next:
A cooling trend will arrive ahead of the storm, with Monday's high temperature expected to reach 67 degrees in downtown Los Angeles, then decrease gradually to 59 on Friday, according to the NWS.
PREVIOUS COVERAGE: Southern California braces for Christmas storm: Timeline
Overnight lows will generally be in the 50s for the beginning of the week, then drop into the 40s in some areas later in the week.
A Tesla motorist drives through the rain near the Eaton Fire burn zone as a powerful atmospheric river storm impacts the region on February 13, 2025 in Pasadena, California. (Photo by Mario Tama/Getty Images)
Safety tips
What you can do:
- Clear Drains and Gutters: Ensure storm drains and home gutters are clear of debris to prevent localized flooding.
- Burn Scar Safety: If you live near a recent wildfire burn area, prepare for potential evacuation. Debris flows can move faster than you can run.
- Secure Outdoor Items: With gusts up to 80 mph possible, secure patio furniture, trash cans, and holiday decorations.
- Travel With Caution: Avoid mountain passes if possible during peak wind periods (Tuesday night–Wednesday) and watch for "Turn Around, Don't Drown" conditions on flooded roads.
The Source: This report is based on information from the National Weather Service and FOX Weather. City News Service contributed.