Climate & Environment · Global

Kelvin waves raise West Coast sea levels, making flooding more favorable as El Niño strengthens

Coastally trapped Kelvin waves are moving along the West Coast, and one has raised sea levels there. More Kelvin waves are coming, while a scientist says the waves alone do not cause flooding.

AI-assisted synthesis · Based on 4 independent reports from 6 outlets · Article text read from 1 of 4 reportsHow it's made

View timeline · 6 entries

6 outlets2 regionsLatest reporting Oct 19, 11:08 PM UTC3 min read

Coverage: Center OnlyL 0 · C 5 · R 0 · 1 unrated

What happened

Key facts

Coastally trapped Kelvin waves are moving along the West Coast (per laist.com, suaragarut.id, kqed.org).
Dillon Amaya, an assistant professor of atmospheric sciences at North Carolina State University, says a Kelvin wave is not a wall of water, a tsunami, or a surfable wave (per laist.com).
Dillon Amaya says Kelvin waves alone do not cause flooding, but make coastal conditions more favorable for flooding (per laist.com).
SuaraGarut.ID's headline says Kelvin waves raise West Coast sea levels as El Niño strengthens (per suaragarut.id, laist.com, kqed.org).
KQED's headline says El Niño can raise West Coast sea levels through Kelvin waves (per kqed.org, laist.com, suaragarut.id).

The brief

A Kelvin wave has raised sea levels on the West Coast, and more are coming, according to NPR’s report published by LAist. The account describes coastally trapped Kelvin waves moving along the West Coast, but does not give a sea-level measurement or specify when the wave raised the water.

Mark Cane, professor emeritus of earth and climate sciences at Columbia University, describes the phenomenon as comparable to water sloshing in an enormous bathtub. Cane says he created one of the first models for forecasting and predicting El Niño.

The account also notes that Lord Kelvin, the British physicist associated with the Kelvin temperature scale, first described the wave in the late 19th century. Dillon Amaya, an assistant professor of atmospheric sciences at North Carolina State University, stresses that a Kelvin wave is not a wall of water, tsunami or wave people can surf.

He says the waves do not cause flooding by themselves. Instead, Amaya says, they make coastal conditions more favorable for flooding; a separate trigger, such as a major storm or very high tides, is needed. The outlet headlines connect Kelvin waves with El Niño in different ways.

SuaraGarut.ID says West Coast sea levels are rising as El Niño strengthens, while KQED’s headline describes how El Niño can raise those sea levels through Kelvin waves.

SURFER Magazine and Yahoo use the phrase “Multi-Headed Monster” for waves approaching California’s coast during a “Super El Niño.” Those headline descriptions do not supply additional measurements or details about coastal impacts.

The central distinction in Amaya’s explanation is between elevated conditions that could make flooding more favorable and the separate weather or tide trigger he says flooding requires. His examples are a major storm and very high tides; the report does not identify either as occurring alongside the sea-level rise.

The account’s practical focus is therefore on the combination Amaya describes: Kelvin waves can alter coastal conditions, while flooding requires an additional trigger. It identifies no particular location, storm or tide event connected to the reported rise, and gives no figure for the water-level change.

The report also says more Kelvin waves are coming, without specifying their timing or magnitude.

Why it matters

Coastal communities along the West Coast could face more favorable conditions for flooding when Kelvin waves coincide with a major storm or very high tides, the triggers Amaya identifies.
Amaya’s explanation distinguishes Kelvin waves from tsunamis and surfable waves, while emphasizing that the waves alone do not cause flooding.
The reported sea-level rise is not quantified, so the account gives no measurement to assess the scale of the change.

What to watch next

Whether additional Kelvin waves move along the West Coast, as the report says more are coming.
Whether a major storm coincides with the coastal conditions Amaya says Kelvin waves make more favorable for flooding.
Whether very high tides coincide with those conditions, the other flooding trigger Amaya identifies.

How it's being covered

Coverage analysisShow details

6 source articles · 6 unique outlets · 4 distinct reports

Outlet political mix: Center Only· 5 Center · 1 unrated

Where the outlets are based: US/Canada 50% · Unknown 33% · Other 17%

Outlet political mix

Center Only

Left

Center

Right

0 outlets

5 outlets

0 outlets

The marker shows coverage balance: each unique outlet counts once. 1 unrated outlet is not included.

Geography

Where the outlets covering this story are based.

6 unique outletsDominant coverage: US/Canada

All6 US/CA3 · 50%Asia1 · 17%Unknown2 · 33%

Coverage imbalance

Coverage is currently concentrated among Center-rated outlets (5 of 5 rated sources); comparatively few Left or Right-rated outlets have published on the event.

How we measure coverage

How outlets' accounts compare

Updat3 does not yet have enough full reports to compare how outlets framed this story.

Timeline

Developments from this story's sources, dated background we compiled and fact-checked, and our earlier coverage. Each row says which.

1879
William Thomson, Lord Kelvin, published a mathematical account of waves in rotating water.
Background · compiled and fact-checked by Updat3
1969
In 1969, meteorologist Jacob Bjerknes described how warmer waters in the eastern tropical Pacific can interact with changes in the trade winds and atmospheric circulation, reinforcing El Niño conditions.
Background · from our historical context
1982
A major El Niño developed in the tropical Pacific, bringing unusually high sea levels to parts of the U.S. West Coast.
Background · compiled and fact-checked by Updat3
1997
A strong El Niño developed in the tropical Pacific, with ocean waves transmitting changes toward the eastern Pacific.
Background · compiled and fact-checked by Updat3
2015
A strong El Niño developed, and unusually high coastal sea levels were documented along parts of the U.S. West Coast during the 2015–16 event.
Background · compiled and fact-checked by Updat3
Jul 2023
The World Meteorological Organization confirmed that El Niño conditions had returned.
Background · compiled and fact-checked by Updat3

How we got here

The 2015–16 El Niño is a useful precedent for understanding how a warming tropical Pacific can affect the U.S. West Coast: during that event, unusually high coastal sea levels were documented along parts of the coast.

In 1969, meteorologist Jacob Bjerknes described how warmer waters in the eastern tropical Pacific can interact with changes in the trade winds and atmospheric circulation, reinforcing El Niño conditions. When those waves reach the eastern boundary of the Pacific, some of their energy can travel poleward along the coast as coastal Kelvin waves.