Dam/Levee Failure

Hazard in Flooding

A low-probability, high-consequence infrastructure hazard: a sudden release of impounded water onto the communities downstream.

Plans also call it: dam failure, dam breach, dam break, levee breach, high hazard potential dam

Talk to us about Dam/Levee FailureAll 73 hazards →

What you’d hand your council

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

Evidence brief for Cedar Ridge County (example)

September 14, 2026

Dam/Levee Failure

Hazard in Flooding, on the established threats & hazards list

Impact
5432112345

Likelihood

Likelihood
3

Possible — Expected occasionally — roughly once in 10 to 50 years (2–10% chance in any year).

Impact
3

Moderate — Notable effects — injuries possible, damage in multiple areas, essential services disrupted for days.

Readiness
4

High — The organization has a well-developed capability to manage this threat or hazard. Plans, personnel, resources, and skills are largely in place, and the capability has been meaningfully tested or demonstrated. Remaining gaps are unlikely to significantly impair performance.

  • 2source documents
  • 58verified mentions
  • 2federal declarations
  • —NRI risk score
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’s National Risk Index doesn’t model Dam/Levee Failure. Your team fills it with local evidence, and Hazzard shows the gap rather than a zero.

How it maps

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

FEMA National Risk Index
Not covered
FEMA declaration incident type
Dam/Levee Break6 declarations on record
NOAA Storm Events type
Not covered
Hazzard category
Flooding, natural hazards

How it connects

The national record

What the federal data says about Dam/Levee Failure

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

6 federal declarations since 1963

Declarations FEMA filed as “Dam/Levee Break”, by year (2026 to date)

0121963: 1 declaration1973: 1 declaration2004: 1 declaration2017: 1 declaration2020: 2 declarations2020: 2197019801990200020102020
OpenFEMA Disaster Declarations Summaries, as of 2026-09-27. Counts distinct disasters; major, emergency and fire-management declarations.

In your plan

What a Dam/Levee Failure 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 Dam/Levee Failure.

  1. Location

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

    Your documents

    No national layer maps Dam/Levee Failure. We draw the geographic extent from your plans, studies and annexes, cited to the page.

  2. Extent

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

    Your documents

    The magnitude your plans use for Dam/Levee Failure (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 Dam/Levee Break 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)

    Your team decides

    No national dataset gives a frequency for Dam/Levee Failure. Your team scores likelihood on your scale from the evidence we organize.

  5. Vulnerability and impacts

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

    Your documents

    The Census population profile and HHS emPOWER counts for context; the consequences themselves come from your plans and exercises.

  6. The assessment itself

    Your team decides

    Likelihood, impact and readiness for Dam/Levee Failure 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 Dam/Levee Failure

  1. 1

    We pull your flood history

    Federal declarations, NRI's inland and coastal flooding ratings, and the mitigation projects FEMA has already funded in your county.

  2. 2

    We read your plans for each cause

    Mitigation plan, floodplain and dam safety material, so Dam/Levee Failure is profiled as its own thing instead of folded into “flooding”.

  3. 3

    You leave with a cited brief

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

Also in Flooding

Preparing for Dam/Levee Failure

Show where Dam/Levee Failure actually reaches, not just that it can.

Flooding is the most common declaration in the country, and each cause plans differently. We separate them in your evidence so the mitigation that follows is aimed at the right water. A person replies within one business day.

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