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Kelvin wave pushes West Coast sea levels higher, raising flood and erosion concerns

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Coverage spectrum

Covered by 5 outlets across the spectrum.

5 articles in total. The spectrum counts each outlet once and leaves opinion out. How we measure bias

A Kelvin wave, a pulse of warm water linked to a strong El Niño, is moving along the West Coast and expected to raise sea levels by roughly six inches to a foot over the coming weeks, according to NOAA and NASA scientists. The surge, moving at about 6 miles per hour, is expected to travel north from California into Oregon and Washington, with effects building through October into February. Scientists say the phenomenon itself is not a breaking wave but a gradual bulge of warm water, and that it could worsen coastal flooding and erosion, especially in areas already affected by storms and climate change. Researchers cited include NOAA oceanographer Michael Jacox and Washington University geophysicist Michael Wysession.

Headline and summary written by Mantle’s AI from the coverage below, under published rules. How this works

What happened

Key points

Each point shows who reports it, from Far Left to Far Right.

  1. A Kelvin wave, a pulse of warm ocean water linked to El Niño, is moving along the West Coast

    Reported byLeftCenterRight

  2. Sea levels are expected to rise by roughly six inches to a foot

    Reported byLeftCenterRight

  3. The wave is moving north at about 6 miles per hour, or 150 miles per day

    Reported byLeftCenter

  4. Effects are expected to continue from October through February

    Reported byLeftCenter

  5. Scientists warn the elevated sea levels could worsen flooding and erosion, especially given existing storm damage

    Reported byLeftCenterRight

  6. NY Post described the event as potentially bringing California's highest sea levels ever recorded

    Reported byRight

What is contested

Where accounts differ

Points the coverage does not agree on, and who says what.

  • The scale and significance of the sea level rise

    The New York Post suggests California could see its highest sea levels ever recorded, while the AP report and Straight Arrow News describe a more measured rise of six inches to a foot that will not by itself cause flooding, according to NOAA scientist Michael Jacox.

How each side tells it

Compare views

  • the left

    1 outlet

    The left side's only supplied coverage is an Associated Press report republished by ABC News, headlined neutrally around the scientific phenomenon and its possible effects.

    A pulse of warm water hitting the Pacific coast could mean erosion and flooding
    ABC NewsLeftAll left-leaning headlines

  • the center

    2 outlets

    Center outlets combine the same syndicated AP explainer with Straight Arrow News's own piece, both framing the event as a scientific phenomenon worth understanding rather than a dramatic threat.

    Kelvin wave incoming: Why the US should care
    Straight Arrow NewsCenterAll center headlines

  • the right

    2 outlets

    The New York Post frames the event dramatically as a 'freak' phenomenon threatening record sea levels, while The Washington Times republishes the same neutral AP explainer used by center and left outlets.

    Sensational language“Freak ocean phenomenon”Describes a well-understood natural phenomenon as bizarre or abnormal, adding drama beyond the facts.More neutral: Kelvin wave phenomenonDisagree with this highlight? takes hold of California coast with seas surging
    New York PostRightAll right-leaning headlines

The words they chose

Language to notice

Words that carry a judgement beyond the facts. Tap a highlighted word anywhere on the page to see why.

  • Left0

    No loaded words in its own voice.

  • Center0

    No loaded words in its own voice.

  • Right3

    massive surgebattered beachesFreak ocean phenomenon

In the outlets’ own words

  • Sensational language

    massive surgeMore neutral: sea level rise

    Amplifies the scale of the event beyond the measured six-inch to one-foot rise described by scientists.

    California’s coast is bracing for a massive surge that could push sea levels up by as much as a foot in the coming days, piling onto…

    Used byNew York Post (Right)

  • Loaded modifier

    battered beachesMore neutral: already affected beaches

    Characterizes the beaches with a dramatic adjective rather than describing specific damage.

    …push sea levels up by as much as a foot in the coming days, piling onto already battered beaches and raising the risk of flooding and erosion.

    Used byNew York Post (Right)

  • Sensational language

    Freak ocean phenomenonMore neutral: Kelvin wave phenomenon

    Describes a well-understood natural phenomenon as bizarre or abnormal, adding drama beyond the facts.

    Freak ocean phenomenon takes hold of California coast with seas surging

    Used byNew York Post (Right)

See the full language guide

See for yourself

Side by side

What each side leads with and what it leaves out. Open a side to read its headlines.

From the left

1 outlet

Leads with

  • scientific explanation of Kelvin waves
  • timing and speed of the surge
  • link to climate change and El Niño

Leaves out

  • NY Post's description of the event as a record-setting phenomenon

Reported by other sides, not found in this side’s coverage.

See the headline from the leftHide the headlines
  • ABC NewsLeftAssociated Press report

    A pulse of warm water hitting the Pacific coast could mean erosion and flooding

    Sea levels along the West Coast will begin to rise by up to a foot this month as a series of pulses of warm water called Kelvin waves hit the shoreline and move north, sparking concerns about beach erosion and flooding in areas already impacted by clim...

    Read at ABC News (opens in a new tab)

    Also published by PBS NewsHour and The Washington Times. It counts once.

From the center

2 outlets

Leads with

  • explanation of how Kelvin waves form
  • expert commentary from geophysicists
  • practical reasons the public should care
See the 2 headlines from the centerHide the headlines

From the right

2 outlets

Leads with

  • dramatic sea level surge
  • risk to California's battered coastline
  • recent unusual ocean events like Malibu flooding

Leaves out

  • specific wave speed and timeline details reported elsewhere

Reported by other sides, not found in this side’s coverage.

See the 2 headlines from the rightHide the headlines

Articles you open from here build My Mix, a private picture of how your reading spreads across the spectrum, kept on this device. What is My Mix?

The left is Far Left and Left together. The right is Right and Far Right together. Every outlet keeps its own five-point rating.

Who reported it when

How the coverage built up

  • Left

    12 hr 42 min later

    Its first report, Oct 3, 10:54 AM EDT

  • Center

    17 hr 32 min later

    Its first report, Oct 3, 3:45 PM EDT

  • Right

    First to report

    New York Post, Oct 2, 10:12 PM EDT

See the order the outlets reported inHide the order
  1. New York PostRightOct 2, 10:12 PM EDT
  2. ABC NewsLeftOct 3, 10:54 AM EDT
  3. The Washington TimesRightOct 3, 3:43 PM EDT
  4. PBS NewsHourCenterOct 3, 3:45 PM EDT
  5. Straight Arrow NewsCenterOct 4, 8:00 AM EDT

Times are the ones the outlets published in their own feeds, in Eastern time. Opinion is left out.

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