Scientists warn a slow-moving, planetary-scale Kelvin wave spawned by an exceptionally strong El Niño could raise sea levels along the California coast by up to a foot, roughly 30 cm. The wave began when trade winds weakened, sending a massive slosh of warm western Pacific water along the equator; one pulse hit the northern tip of South America in late August and has been propagating north toward the US. Researchers at NASA’s Jet Propulsion Laboratory and NOAA’s Southwest Fisheries Science Center say the wave could reach California within days and keep coastal waters elevated for months as El Niño lingers through winter and into early next year. Because global sea level has risen about 8 inches over the last century, that extra foot effectively raises the baseline for high tides and storm surge. Scientists including Nate Mantua and Mike Jacox warn elevated tides expected around Thanksgiving and Christmas, combined with more frequent storms this El Niño brings, will increase flooding and coastal erosion risks. Federal and state agencies are monitoring the event and California officials are taking preparatory steps for a potentially severe season.
David Ho5
Stephen Smith1
HydrologyNL1
