California could be in for another stormy winter next year as climate watchers predict that an El Niño pattern, or warmer-than-normal ocean temperatures in the tropical Pacific Ocean, will form this fall.
A three-year La Niña, or cooler-than-normal ocean temperatures in the equatorial Pacific, officially ended in March.
The changes in the tropical ocean temperatures are among the planet’s most important climate events because they can change how air circulates around the globe.
Low-level surface winds that typically blow from east to west along the equator can weaken and even reverse direction.
That can affect weather patterns around the planet, including temperature and rainfall.
The El Niño Southern Oscillation typically brings more wet weather to the Golden State.
“The jet stream, the area of fast-moving winds about 30,000 to 40,000 feet in the air, kind of serves as a storm highway,” said Tom Di Liberto, meteorologist with the National Oceanic and Atmospheric Administration. “It kind of gets directed more often across the southern tier of the United States, which leads to there being more storms and more rainfall.”
California has had some epic examples.
A strong El Niño in the winter of 1997 and '98 brought storms that pummeled California and caused $500 million in damages. Flooding and landslides damaged property and led to the deaths of 17 people.
It could have been worse, but researchers at the Scripps Institution of Oceanography, led by Tim Barnett, made a bold late-summer prediction that damaging storms were on the way. The warning gave local officials time to prepare.
Another massive El Niño in 2015 and 2016 created so much wave energy that there was record setting erosion along the California coast.
But the weather systems do not always follow the playbook.
La Niña conditions are supposed to bring hotter, drier weather to Southern California. In 2021 and 2022 that is what happened.
But, this winter, California has been drenched by a series of atmospheric rivers. The state’s snowpack is larger than it has been in a decade, and the precipitation moved much of the state out of extreme drought conditions.
“Every El Niño is different, just like every La Niña is different,” said Dan Cayan, a climate researcher at the Scripps Institution of Oceanography. “And we certainly have had pretty dismal El Niño winters precipitation-wise, so we can’t exclude that possibility.”
Climate watchers say El Niños and La Niñas are regular and predictable climate events, but forecasting how they will change any given year’s weather is much harder to predict.
