A powerful "Kelvin wave," triggered by this year's super El Niño, is creeping up the Pacific coast of Central and North America and will soon reach California's shores, where it could raise sea levels by up to 1 foot (30 centimeters) for months, researchers warn.Kelvin waves are a well-known, planetary-scale ocean phenomenon, but this particular forecast has experts worried because it will likely amplify the damage from severe storms, storm surges, flooding and coastal erosion that the record-shattering El Niño is expected to bring this winter.In general, a Kelvin wave is a swell wave that spans thousands of miles and balances Earth's rotation, David Webb, a physical oceanographer at the Nat...