https://www.theguardian.com/us-news/2026/sep/28/california-kelvin-wave
"Concerns are mounting about an ocean phenomenon known as a Kelvin wave that
could raise sea levels along the California coastline by up to a foot, as
scientists say El Niño is supercharging the threat of storm surges and flooding
in the coming months.
As an incredibly strong El Niño continues to develop in the Pacific, the
phenomenon brings with it a strange shift in the ocean. The Kelvin wave
phenomenon is created when trade winds that usually blow from South America
towards Asia die down or reverse in El Niño years, setting off a massive,
slow-moving slosh of water.
Kelvin waves are not like crashing waves at the beach. They are planetary in
scale, spanning thousands of miles. And when a Kelvin wave kicks off, it brings
with it an untold amount of warm water that slowly moves from the western
Pacific, along the equator, towards South, Central and North America.
“You can follow them along … we see the higher sea levels along the equator,
and when the wave reaches the coast of South America, it cannot continue to go
eastward,” Severine Fournier, a research scientist studying ocean circulation
at Nasa’s Jet Propulsion Laboratory, said. “So it goes north and south.”
One such wave hit the northern tip of South America in late August and has
begun moving up towards the west coast of the US. That wave could reach
California shores within days, and when it does, ocean scientists say it may
raise sea levels by up to a foot for months as El Niño lingers and keeps that
warm water trapped along the coast.
Nate Mantua, a research scientist at the National Oceanic and Atmospheric
Administration’s Southwest Fisheries Science Center, explained that in a
typical year, there is a thick layer of warm water in the western Pacific.
“When the wind stops blowing or weakens, the force that’s holding that pile of
water in place goes away, so that water surges or sloshes back towards
California,” he said, noting researchers expect the influence of the Kelvin
wave to linger through the winter and into early next year.
Mantua said Kelvin waves were a natural phenomenon that have been happening for
thousands of years and measured by agencies like Noaa since record-keeping
began. But sea levels have already risen about 8in over the last century,
meaning Kelvin waves will add more water on top of a figure that’s already
going up.
“We can predict a lot of the impacts,” he added, “but not all.”"
Via Susan ****
Cheers,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
