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Flood data
method and limits

The state, county and storm pages of RestoreWorth publish aggregates of public FEMA and National Hurricane Center files. This page holds what they share: what the figures are not, how each comparison is computed, the notes common to the files and every source with its filters.

What these figures are not

Claims are amounts paid, not repair cost; premiums are what NFIP policyholders paid, not a quote. They describe NFIP-insured properties and FEMA programs, not every home or every flood, they mix dollars of different years and disasters, and nothing here predicts the cost, premium, eligibility or claim amount of anyone.

  • A state figure mixes very different counties and flood zones.
  • A county figure can rest on one disaster, and FEMA’s county code may not be the county where every property stands.
  • A storm total counts NFIP-insured buildings with a paid claim, not all the damage of the storm.

How the comparisons are computed

NFIP communities (Community Status Book)

Each community of FEMA’s Community Status Book names its county in a text field; a community is counted in a county when that field names this county alone (matched on the Census 2020 county name of the same State, case, accents and punctuation ignored). A community that names several counties is listed apart on each of them and not counted; one whose county name matches no county is left out. When these two cases exceed 5% of a State’s communities, the State and county pages say so.

CRS class: the Community Rating System class of the community (1 to 10). The CRS discount column is the discount the Status Book lists for that class in the Special Flood Hazard Area (SFHA), the one FEMA’s class table gives. FEMA’s Community Rating System page (retrieved 2026-10-12) states: “Under the National Flood Insurance Program’s pricing approach, the CRS discount is applied to the full-risk premium for all NFIP policies in the Regular Program in a participating community, including policies outside of the Special Flood Hazard Area (SFHA). An individual’s NFIP policy may be excluded from receiving the CRS discount if their structure is deemed to be not in compliance with community floodplain management regulations.” A class therefore discounts the Regular Program NFIP policies of its community (a non-compliant building can be excluded), not the policies of the whole county or State; the communities that extend into other counties are listed apart and not counted. Best class, share classed and oldest map in effect are read from the communities counted in the county; a map whose effective date is after the date of the report is left out of the oldest map. Codes after a date, from FEMA’s field definitions:

Landfalls and National Hurricane Center reports

Storm: the named storm of the National Hurricane Center’s HURDAT2 best track (Atlantic, then Northeast Pacific) with the name and year of the page. Landfall: a HURDAT2 record with identifier L, center of the system crossing a coastline (HURDAT2 format notes); date and time are UTC, wind is the maximum sustained wind in knots, pressure the minimum central pressure in millibars. Strength: the HURDAT2 status; for status HU the category is read from the wind on the Saffir-Simpson Hurricane Wind Scale (category 1: 64-82 kt, 2: 83-95 kt, 3: 96-112 kt, 4: 113-136 kt, 5: 137 kt or higher).

County: the Census 2020 county (cartographic boundary, 1:5,000,000) that contains the HURDAT2 position, or the nearest one within 30 km, with its distance; beyond 30 km no US county is named. HURDAT2 positions are given to a tenth of a degree, so the county is the one nearest the recorded position, not a surveyed landfall point.

Quotes: the first two sentences of the summary of the NHC Tropical Cyclone Report, completed by the first sentences of its synoptic history when the summary has a single usable one. The report text is extracted three ways (pdftotext paragraph and raw modes, pypdf), and a sentence is quoted only when all three hold it character for character, so no extraction artefact is quoted. A storm without a report found at its NHC address says so and quotes nothing.

Notes on the data

Sources, notice and license

Not an official federal report. OpenFEMA terms and conditions. No FEMA or DHS logo or seal is used.

This product uses the Federal Emergency Management Agency’s OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).

The same FEMA figures for AI assistants: RestoreWorth FEMA Data MCP server.

Aggregates published by RestoreWorth Team; no individual record is shown.

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