← Reference notes

Tsunami alert levels: warning, advisory, watch, information statement

Summary

The US tsunami warning centers use four alert levels. A warning means widespread flooding is expected, so evacuate to high ground or inland. An advisory means strong currents or dangerous waves, so stay out of the water. A watch means a tsunami is possible, so be ready to act. An information statement means no threat or none determined yet. A strong quake felt at the coast is a natural warning to move right away.

Draft. License: CC BY 4.0 (this summary). Sources: [S1] NOAA National Weather Service, "Tsunami Alerts" (public domain (US government work)); [S2] NOAA/NWS U.S. Tsunami Warning System (tsunami.gov), "Tsunami FAQ" (public domain (US government work)).

Facts

• id: F1 claim: NOAA tsunami messages for US and Canadian coasts use four alert levels: warning, advisory, watch and information statement. confidence: medium date: 2026-11-02 sources: [S1] license: CC BY 4.0 checked_on: 2026-11-02
• id: F2 claim: A Tsunami Warning means a tsunami that may cause widespread flooding is expected or occurring; evacuation to high ground or inland is recommended, and flooding and strong currents may continue for hours or days. confidence: medium date: 2026-11-02 sources: [S1] license: CC BY 4.0 checked_on: 2026-11-02
• id: F3 claim: A Tsunami Advisory means strong currents or waves dangerous to people in or very near the water are expected or occurring; beach and harbor areas may flood, and people should stay out of the water and away from beaches. confidence: medium date: 2026-11-02 sources: [S1] license: CC BY 4.0 checked_on: 2026-11-02
• id: F4 claim: A Tsunami Watch means a distant earthquake has occurred and a tsunami is possible; people should stay informed and be ready to act. confidence: medium date: 2026-11-02 sources: [S1] license: CC BY 4.0 checked_on: 2026-11-02
• id: F5 claim: A Tsunami Information Statement means an earthquake occurred but there is no threat, or it was far away and the threat is not yet determined. confidence: medium date: 2026-11-02 sources: [S1] license: CC BY 4.0 checked_on: 2026-11-02
• id: F6 claim: Warnings, advisories and watches can be updated or cancelled, and lower levels can be upgraded if the threat turns out to be greater. confidence: medium date: 2026-11-02 sources: [S1] license: CC BY 4.0 checked_on: 2026-11-02
• id: F7 claim: Alerts are spread through local radio and TV, marine radio, Wireless Emergency Alerts, NOAA Weather Radio, NOAA websites such as tsunami.gov, sirens, and local officials. confidence: medium date: 2026-11-02 sources: [S1] license: CC BY 4.0 checked_on: 2026-11-02
• id: F8 claim: Natural warning signs are a strong or long earthquake felt at the coast, a sudden rise or fall of the ocean, or a loud roar from the ocean; NOAA says to move to safety without waiting for an official alert. confidence: medium date: 2026-11-02 sources: [S1] license: CC BY 4.0 checked_on: 2026-11-02
• id: F9 claim: A tsunami is a series of very long waves caused by a large, sudden displacement of the ocean; it is not related to tides, so calling it a 'tidal wave' is incorrect. confidence: medium date: 2026-11-02 sources: [S2] license: CC BY 4.0 checked_on: 2026-11-02
• id: F10 claim: Scientists cannot predict when and where the next tsunami will strike, just as they cannot predict the earthquakes that cause most tsunamis. confidence: medium date: 2026-11-02 sources: [S2] license: CC BY 4.0 checked_on: 2026-11-02

Caveats

• Outside the US and Canada, national agencies use their own alert names; follow local officials.
• The first wave is often not the largest; do not return until officials say it is safe (general guidance; check the source).

Pointers

• id: P1 answers: Current active alerts where: https://www.tsunami.gov/ access: free, public web page

@misc{iil_note_zgfs1eyv,
  author = {{iinventedlight Library}},
  title = {{Tsunami alert levels: warning, advisory, watch, information statement}},
  howpublished = {iinventedlight Library},
  year = {2026},
  date = {2026-11-02},
  url = {https://iinventedlight.com/library/reference/us-gov/tsunami-alert-levels/},
  note = {Permanent ID iil:note:zgfs1eyv. License: CC-BY-4.0. Summary of https://www.weather.gov/safety/tsunami-alerts.},
}

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