Southern California Coastal Flood Warning: Homes, Beaches and Rail Service at Risk

Southern California’s coastal flood warning takes effect Sunday morning, Oct. 25, with high tides threatening low-lying homes and businesses, eroding beaches and disrupting rail travel along the Orange County coast. The National Weather Service has warned of coastal flooding in Orange and San Diego counties through Oct. 29 afternoon, while Los Angeles and Ventura counties face coastal flood advisories.

The National Weather Service warning is scheduled to run from 5 a.m. Sunday to 1 p.m. Thursday. Forecast tides could reach 1 to 1.7 feet above predicted levels, increasing the risk of seawater reaching vulnerable properties and coastal infrastructure. The advisories also warn of possible flooding on beach parking lots, bike paths and harbor walkways. Coastal erosion and rip currents pose additional risks to beachgoers.

High Tides Put Coastal Properties and Beaches at Risk

Newport Beach is among the communities preparing for elevated water levels. Low-lying homes and businesses along the shoreline face potential flooding, while parts of the Balboa Peninsula experienced inundation earlier this month.

The National Weather Service has also identified Long Beach and Malibu as vulnerable to coastal flooding. Seawater can damage roads and structures near the shoreline, particularly around high tide. Beach erosion could further affect vulnerable stretches of coastline, while rip currents increase the danger for swimmers.

Metrolink Suspends Orange County Line Service South of Laguna Niguel

Metrolink plans to suspend Orange County Line service between Laguna Niguel/Mission Viejo and Oceanside from Monday through Friday, because of forecast high tides along the South Orange County coast.

According to Metrolink’s official announcement, trains will continue operating between Los Angeles Union Station and Laguna Niguel/Mission Viejo during the suspension. No alternate bus transportation will be provided for the affected segment.

The agency said the temporary change is intended to limit wider network delays and cancellations if coastal conditions affect the tracks near San Clemente. Crews have also been reinforcing vulnerable sections of the coastal rail corridor with rock and other protective material. Passengers traveling through the affected coastal segment should check Metrolink’s official service updates and arrange alternative transportation during the suspension.

Orange County and Long Beach Prepare for Flooding

Orange County Supervisor Katrina Foley said crews were working to reduce flood risks ahead of the peak tides. “County public works teams and flood district teams have been clearing all the debris from all the gutters, clearing the flood channels, making sure that we don’t have people living in the flood channels,” Foley said, according to ABC7 Los Angeles.

In Long Beach, workers are rebuilding and reinforcing sand berms to help protect the shoreline. Residents in some areas have also been stacking sandbags and clearing floors ahead of the expected high water. Newport Beach officials have urged residents in waterfront and flood-prone neighborhoods to use sandbags, clear gutters when safe and move vehicles away from areas vulnerable to flooding. The measures can reduce property damage but cannot eliminate the risk.

El Niño and Kelvin Waves Add to Coastal Flood Concerns

The latest warning comes amid broader ocean conditions that scientists are monitoring along the West Coast. El Niño and Kelvin waves have been linked to elevated coastal sea levels, although the precise contribution of each factor to the current flooding risk should be established through authoritative scientific sources.

A Kelvin wave is a large-scale ocean wave that can transport warm water and raise sea levels as it moves along a coastline. A previous Kelvin wave raised sea levels along the West Coast by approximately 6 to 8 inches in early October, contributing to flooding that affected Orange County communities. Josh Willis, a climate scientist at NASA’s Jet Propulsion Laboratory, has described the risk as a “triple whammy”: El Niño, high tides and storm surge all arriving simultaneously.

Meteorologist Daniel Amaya predicts the next Kelvin wave will reach San Diego in late October or early November, with several more waves expected through fall and early winter. Jonathan Warrick, a research geologist with the U.S. Geological Survey, said the combination of high tides, Kelvin waves and hurricane-generated waves seen across the region this season has been unprecedented.

Officials are urging residents to avoid driving around barricades or through standing water, monitor road closures and follow local emergency guidance. People in flood-prone areas should secure vulnerable property, while beachgoers should heed warnings about dangerous surf and rip currents. Rail passengers should check Metrolink’s official service updates before traveling and monitor National Weather Service alerts for changes to the flood forecast.