Record-breaking rain lashes California, with two people killed during storm in Sonoma County
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The second of back-to-back atmospheric rivers, which unleashed heavy rain across Northern California this week killing two people, was set to dampen Southern California through Friday morning.
And a potentially more powerful system could douse the Southland before or around Valentine’s Day, heightening concerns for recently burned communities in Los Angeles County.
There is a 30% chance that there could be high amounts of rain between Feb. 12 and 15, Ryan Kittell, a meteorologist with the National Weather Service’s Oxnard office, said Thursday. That’s up from a 20% chance that was forecast a day earlier.
The risk of higher precipitation amounts and subsequent impacts is “definitely higher than most of our storms,” Kittell said.
“It’s still uncertain as far as which outcome is going to happen, but this is definitely higher than normal for those more significant risks,” he said.
Back-to-back atmospheric river storms are set to hit Los Angeles County this week — giving the region much-needed moisture ahead of another potential round of Santa Ana winds.
High amounts of rain would mean 2 to 4 inches or more on the coast and in the valleys, and 4 to 8 inches or more in the mountains and foothills of Los Angeles, Ventura, Santa Barbara and San Luis Obispo counties.
The forecast remains murky, though. There’s a 30% chance of moderate amounts of rain. There is also 30% chance of low rain and a 10% chance of no rain at all.
Forecasters say the most recent models are showing an atmospheric river system hitting Southern California on Feb. 12 or 13.
Atmospheric river storms are long plumes of water vapor that can pour over from the Pacific Ocean into California. They carry so much water that they’re said to be like a river in the sky. Just a few atmospheric river events can bring California from one-third to one-half of its annual precipitation.
California’s snowpack stands at 65% of average for this time of year. After a dry January, major storms are forecast to bring more rain and snow.
This week’s rain comes amid one of the driest starts to the water year in Southern California in modern history. The bone-dry brush, low humidity and Santa Ana winds in January created a devastating combination that fueled massive firestorms in Los Angeles County.
The moisture was a welcome reprieve from fire weather, but officials are also concerned that too much rain too fast might trigger debris flows in the Eaton and Palisades burn scars.
As of Thursday afternoon, that situation had not come to pass.
There’s a very low risk — less than 10% — of rain falling so hard that debris flow and mudslides would be triggered in recent burn areas during this week’s final storm, Kittell said. If significant debris flow does happen, it would be the result of a stray intense storm cell materializing directly over a burn scar.
The Palisades and Eaton burn scars are in areas where enhanced rain rates are likely, meaning it’s possible for mud and water to flow onto local roads. But significant debris flows are unlikely, Kittell said.
Meteorologists say the risk of significant debris and mud flows starts when rain falls at a rate of half an inch per hour.
“In all likelihood, what we’re going to see is a little bit of mud and dirty water flowing onto some of the roads, but it should be very shallow, very minor impacts,” he said of the rainfall expected Thursday and Friday. “But it is worth mentioning that there will likely be something flowing off of those burn scars that might impact some local roads.”
The first atmospheric river that arrived in Southern California earlier this week had packed a wallop in Northern California, but weakened significantly as it moved down the state.
The storm brought modest rainfall amounts to Ventura, Los Angeles, Orange and San Diego counties.
Less than a quarter of an inch of rain had fallen along the Los Angeles coast and the San Fernando and San Gabriel valleys as of Thursday morning. Santa Barbara County saw slightly higher rain totals with just under an inch falling in the Refugio Pass, according to the weather service.
Forecasters say ‘Pineapple Express’ storm will probably be beneficial for Los Angeles and Ventura counties, helping to reduce the risk of wildfires.
So far this week, downtown Los Angeles has seen 0.31 of an inch of rain. The Palisades burn scar has seen 0.63 to 1.16 inches of rain — depending on the exact location within the burn area — and the Eaton burn scar, between 0.31 and 0.54 of an inch.
Forecasters predict the second storm will be of similar strength, but perhaps slightly wetter, dropping between a half an inch and an inch of rain across the region through Friday morning. The mountains and foothills could see a bit more moisture — between an inch and two inches of rain, according to the weather service.
For the Thursday and Friday storm, Long Beach and Redondo Beach could get one-third of an inch of rain; Thousand Oaks and Oxnard, two-fifths of an inch; Santa Clarita and Canoga Park, about half an inch; San Luis Obispo, two-thirds of an inch; downtown Los Angeles, Covina and Fillmore, six-sevenths of an inch; Santa Barbara, about 1 inch; and Ojai, about 1½ inches.
“This is the type of storm that we really want in general — light, steady rain, not all coming down at once,” Kittell said. Minor road flooding and falling rocks on canyon roads are possible.
There’s a 5% to 10% chance of thunderstorms. Rainfall rates are expected to be between one-tenth of an inch per hour and a quarter of an inch per hour, though there could be stronger isolated periods of rainfall in the mountains and foothills.
In Northern California, the storm broke daily rainfall records in San Francisco, San Mateo County and Sonoma County, causing flooding of the Russian River in Guerneville, and near Hopland, in Mendocino County.
Two people died in Sonoma County in less than 24 hours during the storm. Both bodies were pulled from floodwaters, according to the Sonoma County Sheriff’s Office.
On Wednesday evening, the body of a man was pulled from a culvert on Franz Valley Road in Santa Rosa. Early Thursday, the body of another man was recovered from flood waters along Hall Road in Santa Rosa. The individuals have not been identified, according to the sheriff.
On Tuesday morning, a Marin County sheriff’s deputy saved a woman who lost control of her car and ended up in a flooded creek. Video of the rescue, on Platform Bridge Road near Point Reyes, shows the car being overtaken by flood waters as the deputy smashes the back window and helps pull the woman to safety. It is not clear if the woman was injured.
Later on Tuesday, a house in Forestville slid into the Russian River after a rain-saturated hillside gave way, and floodwaters temporarily closed lanes of U.S. 101, Interstate 5 and California 99 across the region.
Whether next week’s storm could have a similar effect in Southern California is unclear. The duration is still hazy, but it’s appearing at this point to be a longer duration event, meaning the rain would fall over a 24-hour period or longer, according to the weather service.
After the rain tapers off Friday night, wind is expected to once again kick up across Southern California. But the fire weather risk will be minimal, given recent moisture.
Los Angeles and Ventura counties could see wind gusts from the southeast and southwest, peaking between 6 p.m. Thursday and Friday at 8 a.m. Gusts could reach 30 mph to 40 mph in San Luis Obispo County, northern Santa Barbara County and L.A. County’s high desert, but are expected to be milder in the Los Angeles metro area and most of Ventura County, with gusts around 10 mph.
At LAX, winds could come out of the east, Kittell said. They won’t be particularly strong, but they may be strong enough to change flight operations, prompting delays.
“This is not a true Santa Ana. It’s more of a northerly type wind event, and it’s dry, but not terribly dry,” Kittell said. “The recent rains are sufficient enough to dampen [and] limit any fire weather concerns, at least for this next push.”
From Friday night through Monday, gusts could reach 12 mph in Covina; 14 mph in downtown Los Angeles and Long Beach; 21 mph in Canoga Park, Thousand Oaks and Fillmore; 22 mph in Oxnard; 26 mph in Santa Clarita; 28 mph in Acton; 41 mph in Lancaster and 58 mph at Pyramid Lake.
Although the recent moisture will help reduce wildfire risk across Los Angeles and Ventura counties, it probably won’t be enough to definitively end fire season given the region’s severe winter rainfall deficit.
Downtown L.A. has received just 0.94 of an inch of rain since the water year began Oct. 1; the average for this time of year — a little more than four months into the water year — is 7.68 inches. The annual average is 14.25 inches.
Despite the rain, drought conditions in Southern California worsened for yet another week, with much of the region now considered to be in “extreme drought” conditions, only the second worse category tracked by the U.S. Drought Mitigation Center.
The center’s latest map released Thursday shows nearly all of coastal Southern California, including most of Los Angeles and Ventura counties and all of Orange and San Diego counties, in “extreme drought.” Much of the rest of the region is considered to be in severe drought.
The rain has not brought enough moisture to stop drought conditions, said Lindsay Johnson, a climatologist with the center who authored the latest map. She said the center’s analysis takes into account rainfall, but also soil moisture, snowpack, fire danger, and other hydrological metrics.
“The longer it’s been dry, the more rain it takes to come back to normal, generally speaking,” Johnson said. “There’s a lot of deficit to make up.”
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