Rare 'High Risk' California Flood Threat As Atmospheric Rivers Target The State Through Friday, Including L.A.
- - Rare 'High Risk' California Flood Threat As Atmospheric Rivers Target The State Through Friday, Including L.A.
Jonathan Belles December 23, 2025 at 2:40 AM
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A dangerous flood and landslide threat has prompted a rare "high risk" forecast for California as a series of atmospheric rivers targets the state this Christmas week, including areas soaked last weekend in Northern California, as well as the L.A. Basin.
High Risk
The next in a series of storms tapping deep plumes of moisture known as atmospheric rivers has meteorologists particularly concerned.
In their excessive rainfall outlook, NOAA's Weather Prediction Center issued a rare "high risk" for parts of Southern California for Wednesday and Wednesday night.
According to NOAA/WPC, these high risk forecasts are only issued on about 4% of days, but have accounted 36% of all flood deaths and 80% of all flood-related damage in the U.S.
Timing
Tuesday night - Christmas Eve: A stronger storm will move into California with heavy rain and strong winds, first in Northern California Tuesday night, then in Southern California overnight, with heavy rain continuing into Wednesday. Locally heavy rain will also spread into parts of the Desert Southwest Wednesday, including Las Vegas and possibly as far east as Phoenix Wednesday night.
Christmas Day - Friday: A second strong Pacific storm is forecast to surge into California Christmas Day, with a second round of heavy rain, strong winds and heavy Sierra snow. Rain showers and mountain snow will linger into Friday. Some locally heavy showers are also possible in parts of the Desert Southwest both days.
Weekend: While a few showers may linger in the Four Corners Saturday, California and the rest of the Desert Southwest will dry out once again.
How Much More Rain, Snow
- Northern California: Widespread 3-inch-plus additional rainfall totals through Friday, with locally 5-inch-plus rainfall are likely in the coastal ranges and foothills of the northern and central Sierra, below snow level. Parts of the Bay Area could see another 1 to 5 inches of rainfall, which would equal about a month's worth of rainfall for San Francisco.
- Southern California: The L.A. Basin from Santa Barbara to Orange County is expected to pick up at least 3 inches of total rain during the Christmas week storms. Higher amounts are likely in the Southland mountains below snow level, where some 8-inch-plus totals are expected, especially along south-facing slopes and foothills. San Diego County may also pick up at least 2 inches of total rainfall. The heaviest rainfall for the region, with rain rates possibly over an inch per hour, is expected Wednesday and Wednesday night, then again Thursday afternoon and night.
- Mountain snow: Several feet of Sierra snow is expected from Tuesday night through Friday. The California snowpack is running signifcantly behind schedule, so this snowfall is very needed.
Additional Rainfall, Snowfall TotalsImpacts
This heavy rain will likely trigger flash flooding and landslides, particularly in hilly and mountainous terrain and areas recently burned by wildfires. Be prepared to evacuate immediately if you live near a burned area. Long-duration flood watches are now in effect for much of California.
At times, rain will also fall at higher elevations than usual in these atmospheric river events, potentially melting existing snowpack adding to the threat of flash and river flooding.
Strong winds next two Pacific storms starting Tuesday night could down trees and knock out power, particularly in areas where the ground is soaked.
This threat of locally flooding rain will also extend into the Desert Southwest, where flood watches are in effect. Expect localized urban flash flooding with water running in normally dry washes and arroyos, including the Vegas Valley.
Current Flood Alerts By The National Weather ServiceRecap
The most recent atmospheric river dumped anywhere from 3 to 14 inches of rain in Northern California's coastal ranges and Sierra foothills from last Saturday night through Monday.
That lead to 69 reports of flooding, 31 reports of landslides and another 22 reports of wind damage in the state from Saturday night through Monday. Among the most serious flash flooding occurred in and near Redding, in far Northern California, where water rescues occurred.
(MORE: Latest Impacts From California)
Jonathan Belles has been a digital meteorologist for weather.com for 9 years. His favorite weather is tropical weather, but also enjoys covering high-impact weather and news stories and winter storms. He's a two-time graduate of Florida State University and a proud graduate of St. Petersburg College.
Source: “AOL Breaking”
