SoCal Beaches Are On High Surf Alert, Prompting Flooding And Erosion Concerns

The National Weather Service has issued a high surf advisory for parts of Los Angeles and Orange counties and a high surf warning in Ventura County starting Thursday.

In Orange County, a high surf advisory is in effect from 8 a.m. Thursday to 2 a.m. Monday, with waves of up to 12 feet expected. The strong waves can result in dangerous swimming and surfing conditions and flooding in parking lots and walkways surrounding the beach.

Even more significant coastal flooding is expected to occur in Ventura County, particularly between Ventura Harbor and Ventura Pier, with waves expected to reach up to 20 feet.

During high tide, there’s a possibility of significant flooding over vulnerable low-lying coastal areas. Coastal roadways and structures could also see damage.

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In Los Angeles County, Hermosa Beach, Manhattan Beach and the Palos Verdes Peninsula beaches will be most impacted by the big waves.

Ariel Cohen, meteorologist with the National Weather Service in Oxnard, said conditions will be “very dangerous … including life-threatening rip currents.”

The coastal flood advisory is in effect from 4 a.m. Thursday to 10 p.m. Saturday in L.A. County and for the high surf advisory, from 4 a.m. Thursday to 10 p.m.Saturday.

Coastal erosion impact

According to the National Weather Service, the high waves will also result in beach erosion.

Patrick Barnard, a research geologist with the U.S. Geological Survey, said this means large waves will move sand offshore.

“We lose the dry beach,” he said.

Earlier this year, homes in San Clemente were red tagged after a record-setting storm pummeled the oceanside cliff they sat on. During a high surf event like the one expected, “areas that are already in a precarious position can be even more exposed or more stressed by conditions,” Barnard said.

There is a “potential for cliff failures, for sure, as those waves are just beating against the base of the cliff more frequently during events like this,” he said.

What's causing the high surf

The high surf will be caused by powerful cyclones on the north central Pacific waters. Those very strong winds, Cohen said, are “creating a significant amount of wave action and energy within the ocean that expands outward and travels far away from where they're being generated, affecting Southern California waters.”