Concerns are growing in California as a slow-moving ocean phenomenon, known as a kelvin wave, is anticipated to reach the state's coastline within days. This event could lead to sea levels rising by up to a foot for several months.
Scientists explain that the kelvin wave is a result of an exceptionally strong El Niño developing in the Pacific. Typically, trade winds blow from South America towards Asia, but during El Niño years, these winds weaken or reverse, initiating a massive movement of water across the ocean.
The wave, which is planetary in scale and spans thousands of miles, carries warm water from the western Pacific towards the Americas. One such wave reached the northern tip of South America in late August and is now moving towards the US west coast.
The National Oceanic and Atmospheric Administration (NOAA) notes that kelvin waves are natural occurrences. However, with sea levels already having risen by approximately eight inches over the last century, this wave is expected to add further water on top of existing levels. Researchers anticipate the wave's influence to persist through the winter and into early next year.
California is taking steps to prepare for a potentially challenging season. Governor Gavin Newsom has declared a state of emergency, mobilising resources ahead of potential winter storms, coastal flooding, and other impacts. The California Coastal Commission has advised residents to prepare by inspecting vulnerable areas, improving drainage, and addressing potential damage causes before severe weather arrives.