Good news for Southern California wildfires: Rain in forecast (but there's a catch)
Southern California is about to get its first significant rainfall in months, bringing desperately needed relief after dry conditions and hazardous winds fueled a series of wildfires in January.
The rain could start as early as Saturday afternoon and last through Monday night with the heaviest rain coming on Sunday, the National Weather Service in Los Angeles said.
Experts have said the end of this tragic fire season would be marked by precipitation, which would bring moisture back to dry vegetation that has been fuel for the fires. Rain would also improve the air quality in the region, which has been poor due to wildfire smoke and ash that spreads far from the fires themselves.
But the storm is not without some fresh risks of its own: After raging wildfires, it doesn't take much precipitation to cause a flood or mudslide.
How contained are the Southern California wildfires?
CalFire provided 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
Here's how much rain Southern California will get
Rain is expected to be widespread, and reach Los Angeles, Ventura and San Diego counties, which have all been on high alert for major infernos while tamping down numerous brush fires. The storm will start Saturday morning over the Bay Area before making its way south later in the day.
In LA and Ventura, between 0.5 and 1 inch of rain is expected, with mountainous areas getting up to 2 inches, forecasters said. The rain is expected to come down intermittently and generally fall at a rate of 0.1 to 0.25 of an inch per hour, with some periods of heavier rain.
There's also a 15%-25% chance of thunderstorms all across the region, the National Weather Service in Los Angeles said.
In the San Diego area, 2 inches or more are expected to fall on the coastal mountain slopes below the snow elevation. Between 0.75 and 1.2 inches could fall in the coastal areas and valleys; 0.5 to 0.75 inches in the high desert; and 0.25 to 0.6 inches in the low deserts, the weather service there said.
Rain brings new fears of mudslides
If the rain falls at a steady, lighter rate, Southern California could be in good shape. That could mean enough rain to help ease the firefighting strain, but not enough to trigger another potential disaster. Heavier rain could mean the chance for flash flooding or mudslides over fresh burn scars.
"Due to increased sensitivity from recent wildfires, moderate to locally heavy rain could result in debris flows and flash flooding in or around burn scars in southern California," the weather service said on Saturday.
If rainfall rates are higher, the risk for debris flow increases, the weather service said. That's because water runoff won't have any vegetation to absorb it and slow it down, and burned soil acts as water-repellant, like pavement. It takes much less rain to trigger a landslide in a burn scar than normal.
According to the weather service, areas downhill or downstream from recent wildfires are most susceptible to flash flooding or debris flow, and that risk can last for years after a fire.
There is a flash flood watch in place from Sunday afternoon to Monday afternoon during the heaviest expected rainfall in all the recent burn areas, including from the Eaton, Palisades, Hughes, Franklin and Bridge fires.