Kelvin wave heads toward California
The gist
An underwater Kelvin wave is heading toward California, possibly raising sea levels 6 to 12 inches.
The extra water stacks on high tides and storm surge, raising coastal flood risk.
How it unfolded
- Sep 21, 2026California Gov. Gavin Newsom declared a state of emergency, saying the state is preparing for potential winter storms and their impacts, including flooding and coastal hazards, and directing agencies to stage equipment and protect infrastructure.
- Sep 23, 2026A Kelvin wave was reported moving along the coast of Mexico and expected to reach California by next month, raising sea levels by 6 to 12 inches; it was expected near San Diego in early to mid-October.
- Sep 25, 2026National Weather Service Climate Prediction Center charts showed sea surface conditions off the charts at the equator.