How Did a La Niña Winter Become So Rainy?

As rain has deluged our parched state since New Year’s Eve, many Californians have found themselves asking a familiar question: Is this somehow because of El Niño?

In the California imagination, the climate pattern known as El Niño has an almost mythological status as a harbinger of prolonged wet spells, while its counterpart, La Niña, is associated with drought. The past three years have been La Niña years.

The continuing procession of storms this winter has drawn comparisons to the famed wet winter of 1997-98, when rain driven by El Niño drenched the Golden State. Californians are bracing for one of the season’s most intense storms to date on Monday and Tuesday.

But Daniel L. Swain, a climate scientist at the University of California, Los Angeles, said that El Niño hasn’t taken over — yet.

“As much as it walks and talks like El Niño, it ain’t,” he said of this winter’s pattern. “We still have La Niña conditions, despite rumors of its demise.”

Even so, long-range forecasts suggest that California will transition into El Niño in the autumn.

So how does this all work? How do we know if El Niño has taken over?

Swain explained, simplifying a bit, that El Niño is essentially one side of a pendulum swing and La Niña is the other. During El Niño, trade winds are weaker, and warm water in the Pacific sloshes toward the western coasts of North America and South America. During La Niña, stronger trade winds push warm water in the other direction, toward the coast of Asia. Ocean temperatures affect the weather.

This dynamic means that the effects of El Niño and La Niña vary in different parts of the world. In parts of the western Pacific, like Indonesia, for example, El Niño tends to produce drier conditions, rather than rain.

In California, the relationship between wet years and El Niño depends on the strength of the pattern, and to some degree on chance. In other words, an El Niño year loads the dice in favor of a wet year, but does not guarantee one.

The latest heavy storms and flooding remind Jan Null, a meteorologist and former lead forecaster for the National Weather Service, of the winter of 2016-17, which was also a La Niña year.

“Every El Niño is not wet, and every La Niña is not dry,” Null said.

Complex advanced predictive tools are showing that by next summer or fall, El Niño will probably be in place, and this time the pattern could be “a pretty strong one,” Swain said. That could bode well for California and the West’s water outlook.

“All of it is fascinating, and also humbling,” he said. “We’re literally predicting the future.”

For more:

Jill Cowan is a national reporter for The Times and is based in Los Angeles.

If you read one story, make it this

The Central Coast prepares for another deluge.

Where we’re traveling

Today’s tip comes from Fritzi Lareau, who recommends a visit to the Monterey Peninsula:

“The peninsula consists of Monterey, Pacific Grove and the village of Carmel. Monterey offers whale watching, sea kayaking, wine tasting and the beautiful Monterey Bay Aquarium. A few miles north, the Elkhorn Slough has a pontoon boat ride through waters teeming with birds, otters, seals and sea lions.

Pacific Grove is quiet, and in the fall thousands of monarch butterflies hibernate there. Driving south toward Carmel (a short drive) you encounter magnificent Point Lobos State Natural Reserve followed by the 17-Mile Drive, which includes upscale Del Monte Lodge, with golf, ocean views and fine dining. Finally, Carmel is a charming, protected artist colony and dog-friendly village with a lovely beach, great bakery and many casual restaurants.”

Tell us about your favorite places to visit in California. Email your suggestions to CAtoday@nytimes.com. We’ll be sharing more in upcoming editions of the newsletter.

Tell us

How are the storms affecting you? Email us at CAToday@nytimes.com with your stories and photos.

And before you go, some good news

Each day, Times Insider editors scour the newspaper for the most interesting facts to appear in articles. As 2022 came to a close, they shared the facts that had most surprised, enlightened or entertained them. Enjoy the collection.

Here’s one about California: Every year, farmers in the state produce more than three billion pounds of almonds, or about 80 percent of the world’s supply.

Thanks for reading. We’ll be back tomorrow.

P.S. Here’s today’s Mini Crossword.

Soumya Karlamangla, Briana Scalia and Maia Coleman contributed to California Today. You can reach the team at CAtoday@nytimes.com.

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