A late-season storm is swinging into California this weekend, bringing heavy rain, mountain snow and strong winds.
It’s the latest in a stormy season in which 51 atmospheric rivers — jets of moisture from the Pacific — struck the West Coast, fueled in part by the strong El Niño climate pattern.
While California did not see the eye-popping rain and snow totals that it did last year, the storm door opened in January and has stayed open well into spring.
“This year had many weaker storms, but so many more of them that we are pretty much normal across the state,” said Chad Hecht, a research meteorologist at the Center for Western Weather and Water Extremes at the Scripps Institution of Oceanography in San Diego. “It’s abnormal to be this normal — we tend to be either really wet or really dry.”
Still, this season marks two relatively wet and snowy years in a row for the state — California is lush and green this spring with full reservoirs and a substantial snowpack that has yet to melt. And the state will enter the summer dry season drought-free for a second straight year.
Though El Niño is rapidly weakening, experts say this winter bore the signs of the climate pattern, both in California and nationally.
Southern California drenched
El Niño — the pattern associated with warmer-than-normal ocean temperatures over the tropical Pacific — tends to bring wet conditions to central and Southern California, and frequent storms drenched the southern part of the state this year, causing significant local flooding in San Diego, Los Angeles, Ventura and Santa Barbara. Though only one strong atmospheric river made a direct hit on California, it was a serious storm that dropped more than 8 inches of rain on Los Angeles between Feb. 4 and 6, the second-highest three-day rain total for the city. The region also saw damaging waves and landslides that often accompany an El Niño winter.
Downtown Los Angeles has received 52.46 inches of rain and counting over the past two years — the wettest back-to-back water years since the late 1800s.
El Niño’s influence tends to be greatest in winter along the southern tier of the United States, and the wet signal extended into the southeastern part of the country, along the Gulf Coast and into Florida.
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“We never have a perfect match, but we could clearly see the fingerprints of El Niño in this winter’s pattern,” Nat Johnson, a research meteorologist at the Geophysical Fluid Dynamics Laboratory at Princeton, said in an interview.
Seasonal outlooks issued last fall picked up the wet signals in the West and Southeast, and hinted at some other wet and dry patterns that emerged.
“For the most part, I would argue that the precipitation pattern that we observed generally corresponded to the forecasts, with some slight differences here and there,” said Andrew Hoell, a research meteorologist at the National Oceanic and Atmospheric Administration’s Physical Sciences Laboratory in Boulder, Colo.
Mountain snow rebounds
The Western snow season got off to a dismal start this year, but snowstorms kicked off in January and continued into March and April.
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California’s snowpack rebounded nicely and is 115 percent of normal, up from 28 percent in early January. This year marks the first time in more than a decade that California has seen consecutive above-average snow years.
Key water regions of the Mountain West also fared well this year, including the upper Colorado River basin, which saw above-average snowpack for the second straight year. Concerning “snow drought” conditions, however, blanket the Northern Rockies to the Pacific Northwest because of drier conditions and above-average winter temperatures.
“This pretty much follows the pattern that we tend to see during an El Niño event — above-average snowpack in the south and below-average snowpack in the north,” Hoell said.
Atmospheric rivers are the wild card
The past two stormy winters in California unfolded under very different climate setups in the equatorial Pacific — La Niña in 2023 and El Niño in 2024.
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“Last year we expected dry and we ended up getting one of the wetter years on record, and that’s because we got more atmospheric rivers than we typically see in a La Niña year,” said Hecht, the Scripps research meteorologist.
Atmospheric rivers are a wild card that can make or break a water year out West — and cause it to veer wildly from seasonal outlooks.
“I think what it tells us is that El Niño and La Niña may tilt the odds in favor of one outcome or another, but still almost anything can happen due to the confounding effects of the chaotic climate system,” Johnson said.
Other high-profile forecast misses over the past decade have fueled skepticism about El Niño’s relevance as a climate predictor. During 2015-2016, the strongest El Niño on record, much of California and the Southwest ended up drier than normal.
“If we look over the entire record since 1950, we generally do see that El Niño-La Niña is a fairly reliable signal on the seasonal time scale,” he said. “Our opinions may have been biased by some of the recent misses, but I don’t think there’s any strong evidence that the signal from El Niño is becoming less reliable.”
