The dark side of El Nino: Sea levels to rise in California as coastal wave surges up west coast

California is bracing for a potentially foot-high rise in sea levels as an immense wave sweeps up the West Coast, a phenomenon tied to the El Nino weather event. Known as a "coastal trapped wave" or "Kelvin wave," this surge is distinct from a tsunami, as it does not crash onto beaches but travels along the coastline, stretching up to 30 kilometers wide.

Oceanographer Dillon Amaya of North Carolina State University explains that this elevated sea state, when combined with storm surges, large swells, or high tides, could significantly increase the risk of flooding and beach erosion. The National Weather Service has issued a coastal flood advisory for much of Southern California due to heavy surf from Hurricane Polo and an emerging El Nino.

Recent storm surges in the region have damaged properties, with homes in Dana Point, Laguna Beach, and Malibu affected. The Kelvin wave, originating in waters near Indonesia when trade winds weaken, results from the suppression of cold water usually found in deeper ocean layers, causing surface temperatures to rise. This ocean warming is what scientists refer to as El Nino.

As the wave reaches the US, it is expected to hit San Diego within a week, already exacerbated by elevated sea temperatures due to the ongoing El Nino.