What is the Kelvin wave on the West Coast?

October 9, 2026

AI Summary

5 min read

What Is the Kelvin Wave on the West Coast?

A strange ocean phenomenon has been creeping up the coast of California, and it recently burst into headlines with a name most people had never heard: the Kelvin wave. Invisible underwater waves that could raise sea levels along the California coastline by up to a foot—what exactly does that mean, and how concerned should anyone be? Dr. Andrew Lysing, an oceanographer who studies marine heat waves at NOAA's Southwest Fisheries Science Center in San Diego, explains that for oceanographers, this is both hilarious and exciting. "It's the kind of thing that us oceanographers have known about for a long time, but it's the kind of thing we've kind of shied away from talking about because it gets a little bit technical." Now, thanks to a colleague who mentioned it in a news interview, the Kelvin wave is having its moment.

How the Wave Forms and Travels

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What you'll learn

1 (01:06) **Strange Ocean Phenomenon on the California Coast** - Introduction to the Kelvin wave, an invisible underwater wave raising sea levels.
2 (01:49) **Oceanographer's Reaction to Kelvin Wave Media Buzz** - Dr. Lysing finds the sudden media attention "hilarious" and "exciting."
3 (02:37) **Visualizing the Wave: Where It Starts and How It Moves** - The wave begins at the far western end of the equator in the Pacific Ocean.
4 (03:55) **The Wave is an Internal Wave, Not a Surface Wave** - This wave is deep in the ocean and transmits energy, not matter.
5 (04:56) **Why Sea Level Rises: Warm Water Expansion** - The thickening warm layer causes the entire water column to expand and sit taller.
6 (05:51) **How Common Are Kelvin Waves?** - They are a symptom of El Niño, but the atmospheric disturbances that cause them can happen anytime.
7 (07:08) **Why the Kelvin Wave is Suddenly in the News** - A colleague, Dr. Dylan Amaya, bravely brought the term up in a news interview.

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Show Notes

A Kelvin wave has reached California and is creeping up the West Coast, raising both sea levels and concerns from government officials. This kind of massive internal wave begins in the western Pacific Ocean and then travels eastward to the Americas along the equator, and then up and down the coastline. While it might raise sea levels up to 12 inches, it stays below the surface instead of crashing on the shore.

Host Flora Lichtman speaks to oceanographer Andrew Leising to get the lowdown on what exactly a Kelvin wave is, and how wary West Coasters should be.

Guest:

Dr. Andrew Leising is a research oceanographer at NOAA Southwest Fisheries Science Center in San Diego, California.

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