Southern California is about to experience its first substantial rainfall in several months, which is crucial for relieving the severe dry conditions and strong winds that have led to numerous wildfires since January.

Rain is anticipated to begin as early as Saturday afternoon and continue into Monday night, with the most intense precipitation expected on Sunday, according to the National Weather Service in Los Angeles.

Experts indicate that this rain could signal the conclusion of this devastating fire season by replenishing the moisture in the parched vegetation that has served as fuel for the wildfires. Additionally, the rain would enhance air quality in the region, which has deteriorated due to smoke and ash drifting from the fires.

However, this storm also brings new dangers: even a small amount of rain can trigger floods or mudslides in areas scorched by wildfires.

Current Status of Southern California Wildfires

CalFire released fire data on Saturday morning:

• Palisades Fire: 23,448 acres burned, 81% contained – started Jan. 7
• Eaton Fire: 14,021 acres burned, 95% contained – started Jan. 7
• Hughes Fire: 10,425 acres burned, 87% contained – started Jan. 22
• Border 2 Fire: 6,500 acres burned, 10% contained – started Jan. 23
• Laguna Fire: 83 acres burned, 90% contained – started Jan. 23

Forecasted Rainfall for Southern California

Rain is expected to be widespread across Los Angeles, Ventura, and San Diego counties, all of which have been on high alert for significant wildfires while battling several brush fires. The storm is forecasted to initiate on Saturday morning over the Bay Area before moving southward later in the day.

In Los Angeles and Ventura, rainfall of 0.5 to 1 inch is predicted, with mountainous regions potentially receiving up to 2 inches, forecasters report. The rain is likely to be intermittent, generally falling at a rate of 0.1 to 0.25 inches per hour, with some heavier bursts expected.

There is also a 15%-25% chance of thunderstorms throughout the region, according to the National Weather Service in Los Angeles.

In the San Diego region, areas on the coastal mountain slopes could see 2 inches or more, while coastal areas and valleys might receive between 0.75 and 1.2 inches; high desert areas are expected to get 0.5 to 0.75 inches, and low deserts may see between 0.25 and 0.6 inches, as reported by the local weather service.

Concerns About Mudslides with Rain

If the rainfall is light and steady, Southern California might weather the storm well. This could provide enough moisture to relieve strain on firefighting efforts without presenting a significant risk of disasters. However, heavier rainfall could lead to flash flooding or mudslides over recently burned areas.

“Given the heightened sensitivity from recent wildfires, moderate to heavy rainfall may cause debris flows and flash flooding in or near burn scars in southern California,” the weather service commented on Saturday.

Increased rainfall rates raise the likelihood of debris flow due to runoff, which can’t be absorbed by burnt vegetation, leaving the ground resembling water-resistant pavement. Consequently, it takes far less rainfall to provoke a landslide in these scorched areas than it would under normal circumstances.

The weather service warns that regions downhill or downstream from recent wildfires are particularly vulnerable to flash flooding or debris flows, with this risk potentially lasting for years following a wildfire event.

A flash flood watch is in effect from Sunday afternoon to Monday afternoon, coinciding with the heaviest anticipated rains in areas affected by the Eaton, Palisades, Hughes, Franklin, and Bridge fires.