What are sneaker waves? Heart-stopping video shows how powerful surges can be dangerous

The massive rogue wave that crashed over beachside spectators in Ventura on Thursday, sending eight to the hospital with moderate injuries, is known as a “sneaker wave,” officials said.

The powerful waves are created by larger than average swells that can suddenly and without warning surge much farther inland than expected, breaking over rocks and lifting logs or driftwood onto the beach with deadly force, according to the National Weather Service.

A video posted online by the Ventura County Fire Department shows at least a dozen people watching swells from the sea wall near South Seward Avenue Thursday morning before quickly scattering when they saw a massive wave barreling toward them. Several people were swept up by the water, which flooded area streets.

Some sneaker waves can surge more than 150 feet up the beach, catching people off guard, causing them to lose their footing and even sweeping them back into the ocean, according to the NWS.

In Northern California, Antonio Maffei caught another dramatic moment on camera when a wave crashed over the seawall Thursday and caught several bystanders off guard.

“When I saw the storms and everything, I was like ‘I’ve gotta get out there and start filming,” he said.

Maffei, 21, has family in Pacifica and has filmed past weather events there.

“It’s always a great spot for some good waves,” he said.

On Thursday, there was a “storm surge, barometric pressure, and we just got this huge push,” which coincided with “higher than normal tides,” he said.

“It came over the wall and people were way too close,” he said, noting that several got knocked over by the surging water.

Though everyone appeared to be OK after the incident, Maffei said his video was a reminder: “Never turn your back to the ocean.”

A coastal flood and high surf warning remains in effect in Ventura County and the Bay Area through Saturday.

Ariel Cohen, meteorologist for the NWS Oxnard office, said he can’t emphasize enough the power of these sudden surges of water and warned people to stay away from the beach as long as these dangerous conditions remain in place.