El Niño is lifting California’s coastal waters

El Niño is expected to raise sea level along California’s coast by about one foot by mid-October as water moves northward from waters off Mexico and Central America.[4] The increase is arriving through a coastal “Kelvin wave” and represents an early significant effect of the powerful El Niño developing in the tropical Pacific.[4] Why it matters: The elevated baseline would leave California’s coast facing higher water levels as winter storms approach, increasing the relevance of coastal flood monitoring.[4] Key insights: The expected rise is being driven by a large volume of water moving northward rather than by a permanent one-foot change in long-term sea level.[4] | The coastal “Kelvin wave” links conditions in the tropical Pacific and waters farther south to California’s near-term coastal levels.[4] Cheatsheet facts: What changed: California’s coastal sea level is projected to rise by about one foot by mid-October under El Niño’s influence.[4] | Why now: A coastal “Kelvin wave” is carrying water north as a powerful El Niño takes shape in the tropical Pacific.[4] | Watch next: Monitor measured California coastal sea levels through mid-October and their overlap with incoming winter storms.[4]