Atmospheric River Sparks Urgent Warning for California Beachgoers

California meteorologists have issued an urgent warning for beachgoers regarding fatal conditions created by an ongoing atmospheric river.

California has faced a slew of atmospheric rivers this winter that have caused devastating floods and landslides. Another moisture-laden storm arrived in the Golden State on Sunday and is working its way south. On Tuesday, impacts from the storm were felt in the Los Angeles region, prompting meteorologists to warn residents of life-threatening waves.

Atmospheric rivers are a "long, narrow region in the atmosphere—like rivers in the sky—that transport most of the water vapor outside of the tropics," according to the National Oceanic and Atmospheric Administration.

"Powerful waves and strong rip currents will pose an exceptional risk of ocean drowning and damage to coastal structures like piers and jetties. Large breaking waves can cause injury, wash people off beaches and rocks, and capsize small boats near shore," a National Weather Service (NWS) high surf warning said. "Everyone should remain out of the water due to life-threatening surf conditions. Stay off of jetties, piers, and other water side infrastructure."

The warning was issued on Tuesday morning and will remain in effect until 9 p.m. local time. San Luis Obispo County Beaches and Santa Barbara County Central Coast Beaches.

Some waves reached 20 feet high. Waves can often be a spectacle for beachgoers, and in late December, a rogue wave crashed into onlookers on Ventura Beach. Some of the onlookers attempted to flee, and others were swept backward toward the sea wall as the wave pulled in. The wave's force was so strong that it pushed a parked car away from the shoreline.

Eight people were treated in hospital for injuries sustained by the exceptionally high waves along the California coast that same day.

"We're not expecting anything like we had in December last year. That was a really large surf combined with really high tides that allowed the waves to get deeper inland," NWS meteorologist Ryan Kittell told Newsweek.

However, Kittell advised that the waves are still dangerous.

"People like to go look at the waves, and it's really important for people to stay as far back, farther back than they think, because a big set can come without notice," he said.

The conditions were so concerning that the NWS office in Los Angeles issued a warning on X, formerly Twitter, as well.

"The WAVES ARE LARGE today over nearly all beaches thanks to a big 10-15 foot long period west swell," the NWS office posted. "These waves are very DANGEROUS. STAY FAR BACK from the waves and OFF THE ROCKS. A surprise large set can come without notice."