{"id":770924,"date":"2026-09-15T00:52:13","date_gmt":"2026-09-15T00:52:13","guid":{"rendered":"https:\/\/www.newsbeep.com\/uk\/770924\/"},"modified":"2026-09-15T00:52:13","modified_gmt":"2026-09-15T00:52:13","slug":"kelvin-wave-poses-new-threat-to-socal-coastal-cities","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/uk\/770924\/","title":{"rendered":"Kelvin wave poses new threat to SoCal coastal cities"},"content":{"rendered":"\n

Coastal communities are beginning to assess the damage from waves and flooding as Southern California braces for more potentially destructive conditions from a \u201ccoastally trapped Kelvin wave.\u201d<\/p>\n

Homes from south Orange County to Malibu were flooded and severely damaged. Erosion chewed away the coast from Carlsbad to Long Beach.<\/p>\n

Laguna Beach<\/a>, Dana Point<\/a> and Carlsbad<\/a> last week declared local states of emergency, citing coastal erosion and sand loss from the effects of a south swell brought on by Hurricane Marie. El Ni\u00f1o typically results in an unusually active hurricane season in the eastern Pacific, which is where Hurricane Marie formed.<\/p>\n

\u201cI\u2019d been chatting with other cities and city managers up and down the coast, and I think we all had different levels of damage,\u201d Laguna Beach City Manager Dave Kiff said. \u201cI think Laguna\u2019s was among the greatest, or most significant, but everybody talked about concern about sand and sand replenishment. They do have sand replenishment projects, from Newport to Huntington to Seal Beach, and then there\u2019s some farther down south.\u201d<\/p>\n

\"Lifeguard <\/p>\n

A lifeguard tower was tied into place Sept. 9 after waves from Hurricane Marie eroded the sand at Thalia Street Beach in Laguna Beach.<\/p>\n

(Don Leach \/ Daily Pilot)<\/p>\n

Orange County officials announced<\/a> that they were activating their emergency operations center, which is required when two cities in the county proclaim a local emergency.<\/p>\n

\u201cOur coastal cities are experiencing serious damage, and the county is mobilizing our emergency response,\u201d Orange County Board of Supervisors Vice Chair Katrina Foley said in a statement.<\/p>\n

Transportation officials posted a video showing severe erosion jeopardizing the train tracks<\/a> used by Metrolink in San Clemente, with strong ocean waves crashing on the tracks and sediment crumbling onto the rocks below. \u201cIt is that serious,\u201d Metrolink said in the post.<\/p>\n

In San Diego County, Carlsbad declared a local emergency <\/a>in an effort to save Carlsbad Boulevard, also known as Old Highway 101, from severe erosion.<\/p>\n

\"Waves <\/p>\n

Waves inundate homes along Beach Road in Dana Point on Sept. 8.<\/p>\n

(Kayla Bartkowski \/ Los Angeles Times)<\/p>\n

So what\u2019s next?<\/p>\n

Another El Ni\u00f1o-influenced phenomenon \u2014 a \u201ccoastally trapped Kelvin wave\u201d \u2014 is moving up the coast of Mexico and will soon hit the U.S. West Coast.
The winter is expected to bring more damaging storms. Government forecasters say there\u2019s now a 75% chance this latest El Ni\u00f1o will be stronger than any other since 1950. There is a 98% chance that El Ni\u00f1o will be \u201cvery strong\u201d for the three-month period ending in December, the National Oceanic and Atmospheric Administration\u2019s Climate Prediction Center said Thursday.<\/p>\n

Here\u2019s a rundown of what we know:<\/p>\n

1. Kelvin is key<\/p>\n

Until recently, Kelvin waves were a pretty obscure concept. But they\u2019re fundamentally at the heart of El Ni\u00f1o: a climate pattern in which the ocean waters in the central and eastern equatorial Pacific heat up and spur changes in the atmosphere that can affect weather around the world.<\/p>\n

Coastally trapped Kelvin waves have been known to exist for decades, as long as scientists have understood El Ni\u00f1o. \u201cCoastally trapped\u201d means they must follow a coastal boundary, with the shoreline to their right in the Northern Hemisphere, said Michael Jacox, research oceanographer with the NOAA\u2019s Fisheries\u2019 Ecosystem Science Division.<\/p>\n

Only recently have computational capabilities progressed to the point that scientists such as Dillon Amaya have been able to model and track<\/a> the waves.<\/p>\n

\u201cNow scientists have a way of seeing these things unfold in real time, and not to mention we\u2019re experiencing one of the largest El Ni\u00f1os on record, which is going to correspond with some of the largest coastally trapped waves on record,\u201d according to Amaya, an expert on this type of wave and an assistant professor in North Carolina State University\u2019s Department of Marine, Earth and Atmospheric Sciences.<\/p>\n

As El Ni\u00f1o develops, the typical east-to-west trade winds along the equator weaken or even reverse, \u201cwhich allows a lot of really hot water and high sea surface heights to slosh back from the far western equatorial Pacific, where they typically sit, all the way to the east,\u201d said Amaya, who earned his doctorate in oceanography from the Scripps Institution of Oceanography at UC San Diego.<\/p>\n

That means typically warmer water, such as around Indonesia, moves east to a normally cooler part of the Pacific, near Peru \u2014 pushed along by Kelvin waves. The Kelvin waves that move here are called \u201cequatorially trapped Kelvin waves,\u201d meaning these waves remain confined along the equator. <\/p>\n

Upon hitting South America, the Kelvin wave splits into two, one heading north, toward California, and the other heading south.<\/p>\n

2. Rising sea levels<\/p>\n

This is when the Kelvin waves become coastally trapped.<\/p>\n

\u201cAlong the coast, these waves elevate sea levels, increase ocean temperatures, and push cold, nutrient-rich waters deeper below the surface,\u201d Jacox said.<\/p>\n

As they travel, Kelvin waves can raise sea levels by as much as 6 to 12 inches \u2014 potentially for months.<\/p>\n

\u201cThose elevated sea levels, when combined with passing weather or storms, can substantially increase flood risk and risk for things like beach erosion,\u201d Amaya said.<\/p>\n

\"A <\/p>\n

Homes on the Long Beach Peninsula are slammed Sept. 8 by a wave resulting from a swell caused by the remnants of Hurricane Marie combined with a 6-foot-high tide.<\/p>\n

(Kelvin Kuo \/ Los Angeles Times)<\/p>\n

3. Timing<\/p>\n

The coastally trapped Kelvin wave is currently on the west coast of Mexico. Amaya said he expected the wave to enter the Gulf of California on or around Saturday. Once there, it will take about 11 days for the wave to hug the gulf\u2019s U-shaped coast and, from there, another seven days for it to travel from the southernmost tip of the Baja California peninsula \u2014 Cabo San Lucas \u2014 to San Diego.<\/p>\n

It\u2019ll then take about two to three days to reach L.A., and another two to three more to get to San Francisco.<\/p>\n

That would put the wave\u2019s arrival in Southern California in early October, although the exact timing remains uncertain.<\/p>\n

\u201cThey\u2019re pretty epic,\u201d Amaya said. \u201cThey travel something like [15,500 miles] all the way from the western equatorial Pacific up … to the Gulf of Alaska, and it takes about 120 days.\u201d<\/p>\n

4. Impact<\/p>\n

This isn\u2019t a surfable wave, and it wouldn\u2019t be overtly noticeable to swimmers or boaters. But it is expected to increase the sea level off the California coast by another 6 inches or so, and its effects could last months.<\/p>\n

It might not sound like much, but another 6 inches of sea level rise could further bludgeon the already battered California coast, especially if combined with the effects from a storm.<\/p>\n

\u201cWe saw why that\u2019s important recently, with houses across Southern California getting battered, especially at those high tides. We had hurricane-generated swells and high tides, and the combination was extremely damaging to these homes,\u201d said Jonathan Warrick, research geologist with the U.S. Geological Survey. \u201cWhen the water level is extra high, a foot or more higher than we expect it to be, then it can really wreak havoc.\u201d<\/p>\n

As it stands, the Golden State has already experienced about a foot of sea level rise over the last 125 years from human-caused global warming and the melting of the polar ice caps. And lately, the state has also seen abnormally high tides.<\/p>\n

Turner writes for Times Community News.<\/p>\n