El Niño could bring rare "Kelvin Wave" phenomenon to Southern California
With a powerful El Niño already predicted to batter Southern California over the winter, forecasters are also cautioning residents to be wary of another phenomenon that may come along with it.
The National Oceanic and Atmospheric Administration recently reported that they are tracking "Kelvin waves," which could bring even further damage to a coastline that is already reeling from damage that has left dozens of homes damaged or uninhabitable in recent weeks.
According to NOAA, Kelvin waves "travel underwater, but produce small changes in sea level ... that are measurable at tide gages along the coast and from satellites." The phenomenon, which is expected to reach Southern California by the end of October after moving north from the Pacific Ocean off the coast of Mexico, brings the sea level higher and could cause even further erosion, damage and flooding in coastal communities.
"It is somewhat remarkable we're even talking about Kelvin waves," said Daniel Swain, a climate scientist for University of California Agriculture and Natural Resources. "You can think of it more like a very broad, hundreds of miles wide, but shallow bulge in the height of the ocean surface. So maybe a foot or so."
Swain says that while the waves aren't typically visible to the naked eye, they can compound coastal erosion by raising the sea level after they become coastally trapped.
"Every two or three inches counts in terms of the damage. ... So, you can have cresting waves from a storm that aren't related to the Kelvin wave, but now we're working with a higher baseline," he said. "We're already seeing problems in coastal Southern California with coastal erosion."
NOAA reports that Kelvin waves have already been impacting the coast since June. In the months since, communities in Malibu, Long Beach, Dana Point, Laguna Beach and San Clemente have seen flooding, erosion and damage to some homes.
Dillon Amaya, a marine scientist and assistant professor at North Carolina State University, says that advances in technology allow scientists to better track Kelvin waves.
"My job as a scientist at this point is to, you know, let the public know that this thing is coming. We can see it coming, and to prepare for the potential impacts accordingly," Amaya said.
He warns that once the system arrives in Southern California, the water won't return to its normal base level for months, and that any storm or high tide during that time period could be catastrophic.
