California Coast Faces Major Sea Level Surge Due to El Niño Phenomenon

California's coastline is preparing for a significant rise in sea levels, with an event known as a "coastal trapped wave" or "Kelvin wave" expected to push ocean levels up by as much as a foot in the coming days. This phenomenon, a consequence of El Niño, is already contributing to unusually high seas and poses increased risks of flooding and erosion along the battered coast.

The Kelvin wave is characterized by a large, sustained bulge of water that extends across a wide offshore area, impacting sea levels along the California coast. This surge arrives at a time when coastal communities are already contending with a series of unusual ocean events and heavy storms.

Recent weeks have seen damaging waves crash over roads in Malibu and cause flooding and erosion in areas like Long Beach, where some homes were inundated and cars damaged by high surf. The elevated sea levels from the Kelvin wave are anticipated to worsen these impacts.

According to Dillon Amaya, an oceanographer at North Carolina State University, an increase of just two to four inches in background sea levels can double the risk of flooding. The current situation is particularly concerning because the Kelvin wave is occurring concurrently with other factors that are already stressing the California coast, including warmer sea temperatures and ongoing erosion from recent storm activity.

Mark Merrifield, director of the Center for Climate Change Impacts and Adaptation at the Scripps Institute of Oceanography, noted to the New York Times that the combination of these factors could lead to the highest sea levels ever recorded in California. The Kelvin wave itself is a product and a symptom of El Niño; as the massive bulge of water travels across the Pacific, it suppresses the upwelling of colder deep-ocean water, contributing to the warmer surface temperatures characteristic of El Niño conditions.