Southern California, particularly the Los Angeles region, is bracing for heavy downpours and a significant chance of widespread flooding through Christmas Eve.

Under a rare Level 4 (out of 4) excessive rainfall risk, certain locations immediately north of Los Angeles — including Santa Clarita and Glendale — may accumulate an entire month’s typical precipitation over the span of just a few days.

Torrential rains began sweeping Sunday through Northern California as another powerful atmospheric river storm system arrived. At least one fatality has been reported, with certain locations already recording close to a foot of accumulated precipitation.

Per the FOX Forecast Center, the system is projected to strengthen upon reaching the shore, generating coastal wind gusts as high as 80 mph. (RELATED: Strong Atmospheric River Set To Blast California With Heavy Rain, Mountain Snow Through Christmas)

An evacuation alert has been put in place for regions recently affected by wildfires, particularly those with burn scars. According to the Los Angeles Fire Department, this warning covers potential debris flows and is scheduled from 11 a.m. to 11 p.m. Thursday.

Fire authorities are advising residents of Pacific Palisades to get ready for potential evacuations as well. Check the City of Los Angeles website for the most current information on evacuation orders.

A high risk designation — the maximum level — signals that major, broad-scale flash flooding is anticipated in the affected regions.

High risk alerts are issued on roughly 4% of days (encompassing both tropical and non-tropical events), yet this category is responsible for 39% of all flood-related deaths and 83% of flood damages across the continental United States, based on studies conducted by meteorologists at the Weather Prediction Center.

Key Messages for the Atmospheric River affecting California and adjacent areas have been updated. There is a HIGH RISK of flash flooding Wednesday along the southern slopes of the Transverse Range just outside Los Angeles. Find your local forecast at https://t.co/pGx1JRZLBI. pic.twitter.com/9WajjzjReF

— NWS Weather Prediction Center (@NWSWPC) December 22, 2025

Studies indicate that on 6% of high-risk flood days, there is at least one death or injury, while 62% of these days result in damages of at least $1 million.

On a day with a high-risk flood alert, floodwaters could overwhelm locations such as the daily commute to work or school, public transit systems, parking lots, the road where people reside or even their own house — including places that have no history of flooding.

Authorities emphasize the slogan “Turn Around, Don’t Drown.” The Federal Emergency Management Agency (FEMA) reports that nearly half of all fatalities from flash floods occur in vehicles.

The upcoming rainfall may affect close to five million residents, with substantial precipitation expected throughout the Transverse Ranges and extending into Southern California. Hourly rain rates could reach up to one inch. (RELATED: Can You Expect White Christmas? Here’s The Weather Outlook For Jesus’ Birthday)

According to the FOX Forecast Center, the anticipated heavy rainfall totals are likely to trigger multiple mudslides. This event has the potential to make the Christmas Eve through Christmas Day period one of the wettest on record for Los Angeles.

Residents in proximity to recent burn scars, such as those from the Palisades and Eaton Fires, are urged to implement safety measures without delay. The National Weather Service (NWS) explains that wildfire ash forms burn scars — a water-repellent layer on the soil that hinders absorption of rainwater, making these zones highly susceptible to flash flooding and debris flows.

Flood watches continue across most of California, staying active through at least Friday.

Stay informed by monitoring any official alerts issued by the NWS, as they will notify residents of potentially life-threatening flooding in impacted areas.