Tsunami

Hazard in Coastal and Tropical Hazards

A rare, high-consequence coastal hazard where waves arrive minutes to hours after a distant or nearby earthquake.

Plans also call it: tsunami inundation, seismic sea wave

Talk to us about TsunamiAll 73 hazards →

What you’d hand your council

The first page of a Tsunami evidence brief: likelihood, impact and readiness on your own scale, every figure sourced.

Evidence brief for Cedar Ridge County (example)

September 14, 2026

Tsunami

Hazard in Coastal and Tropical Hazards, on the established threats & hazards list

Impact
5432112345

Likelihood

Likelihood
4

Likely — Expected within the decade — roughly once in 1 to 10 years (10–100% chance in any year).

Impact
4

Major — Severe effects — casualties possible, serious damage across a significant share of the jurisdiction, essential services disrupted for weeks, outside assistance needed.

Readiness
2

Low — Some elements of capability are in place, but important gaps remain that could significantly limit the organization's ability to perform effectively. Additional development is needed before the capability can be relied upon.

  • 2source documents
  • 58verified mentions
  • 2federal declarations
  • 91.6NRI score, relatively high
Worked example: Cedar Ridge County is fictional. The scores illustrate the format and are nobody's decision. Open a full sample brief →

The national record

FEMA National Risk Index: Tsunami

$1.1B
expected loss a year, nationally
8
counties rated high or very high

Your county’s own rating is the first thing we pull.

How it maps

The same hazard in the vocabularies your plan and FEMA already use.

FEMA National Risk Index
Tsunami (TSUN)one of the 18 hazards NRI scores per county
FEMA declaration incident type
Tsunami3 declarations on record
NOAA Storm Events type
Tsunami
Hazzard category
Coastal and Tropical Hazards, natural hazards

How it connects

Often follows

The national record

What the federal data says about Tsunami

The same national sources a Hazzard brief starts from. For your jurisdiction we narrow each one to your county and its neighbors.

Where Tsunami is rated high

Share of each state's counties FEMA rates Relatively High or Very High

Alabama: not rated for TsunamiAlaska: 0 of 18 counties rated high (0%) · $50M expected loss a yearArizona: not rated for TsunamiArkansas: not rated for TsunamiCalifornia: 2 of 20 counties rated high (10%) · $192M expected loss a yearColorado: not rated for TsunamiConnecticut: not rated for TsunamiDelaware: not rated for TsunamiDistrict of Columbia: not rated for TsunamiFlorida: not rated for TsunamiGeorgia: not rated for TsunamiHawaii: 2 of 5 counties rated high (40%) · $103M expected loss a yearIdaho: not rated for TsunamiIllinois: not rated for TsunamiIndiana: not rated for TsunamiIowa: not rated for TsunamiKansas: not rated for TsunamiKentucky: not rated for TsunamiLouisiana: not rated for TsunamiMaine: not rated for TsunamiMaryland: not rated for TsunamiMassachusetts: not rated for TsunamiMichigan: not rated for TsunamiMinnesota: not rated for TsunamiMississippi: not rated for TsunamiMissouri: not rated for TsunamiMontana: not rated for TsunamiNebraska: not rated for TsunamiNevada: not rated for TsunamiNew Hampshire: not rated for TsunamiNew Jersey: not rated for TsunamiNew Mexico: not rated for TsunamiNew York: not rated for TsunamiNorth Carolina: not rated for TsunamiNorth Dakota: not rated for TsunamiOhio: not rated for TsunamiOklahoma: not rated for TsunamiOregon: 2 of 7 counties rated high (29%) · $143M expected loss a yearPennsylvania: not rated for TsunamiRhode Island: not rated for TsunamiSouth Carolina: not rated for TsunamiSouth Dakota: not rated for TsunamiTennessee: not rated for TsunamiTexas: not rated for TsunamiUtah: not rated for TsunamiVermont: not rated for TsunamiVirginia: not rated for TsunamiWashington: 2 of 15 counties rated high (13%) · $231M expected loss a yearWest Virginia: not rated for TsunamiWisconsin: not rated for TsunamiWyoming: not rated for Tsunami
  • None
  • Up to 10%
  • 10–25%
  • 25–50%
  • Over 50%
  • Not rated
FEMA National Risk Index v1.20.0, county table

3 federal declarations since 2011

Declarations FEMA filed as “Tsunami”, by year (2026 to date)

0242011: 3 declarations2011: 32020
OpenFEMA Disaster Declarations Summaries, as of 2026-09-27. Counts distinct disasters; major, emergency and fire-management declarations.

In your plan

What a Tsunami profile needs, and where each part comes from

A local hazard mitigation plan profiles each hazard the same way (44 CFR 201.6). Here is how Hazzard fills each part for Tsunami.

  1. Location

    44 CFR 201.6(c)(2)(i)

    National data

    FEMA's National Risk Index rates Tsunami for every county. We place yours against its neighbors and the state, then add what your plans map in more detail.

  2. Extent

    44 CFR 201.6(c)(2)(i)

    Your documents

    The magnitude your plans use for Tsunami (a scale, a depth, an acreage, a duration), read from your documents and cited, so the profile states the strength you plan for.

  3. Previous occurrences

    44 CFR 201.6(c)(2)(i)

    National data

    Every FEMA declaration filed as Tsunami that included your county, back to 1953, alongside the events your own records and after-action reports describe.

  4. Probability of future events

    44 CFR 201.6(c)(2)(i)

    National data

    NRI's annualized frequency for your county, and the declaration history, drafted into a likelihood on your own scale for your team to accept or change.

  5. Vulnerability and impacts

    44 CFR 201.6(c)(2)(ii)

    National data

    NRI's expected annual loss and social vulnerability for your county, the Census population profile and HHS emPOWER counts, with the impacts your plans already describe.

  6. The assessment itself

    Your team decides

    Likelihood, impact and readiness for Tsunami are drafted with every source attached, and a person on your team accepts each one. Hazzard never records a score on its own.

How we can help

How we’d help you prepare for Tsunami

  1. 1

    We pull your coastal record

    Hurricane and coastal declarations, NRI's hurricane, coastal flooding and tsunami ratings, and the mitigation FEMA has already funded.

  2. 2

    We read the plans you already have

    Mitigation plan, evacuation and coastal material, so what they say about Tsunami is cited rather than assumed.

  3. 3

    You leave with a cited brief

    Likelihood, impact and readiness for Tsunami on your own scale, every figure tied to its source, ready for the planning team or the council.

Also in Coastal and Tropical Hazards

Preparing for Tsunami

Plan for Tsunami with the record of your own coastline.

Coastal hazards arrive together: wind, surge and erosion in one event. We keep their evidence apart so each gets its own score and its own actions. A person replies within one business day.

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