Map Explainers guides.
Filter OpenFEMA declarations by incident type, designated area, and declaration dates to document federal disaster history. A county listing does not show which buildings flooded.
County policy totals from OpenFEMA show coverage activity for the selected period and geography. They should not be converted into a parcel hazard score or an estimate of uninsured properties.
Build a county loss table from OpenFEMA’s redacted NFIP claims fields and retain the event periods and dataset date. Aggregated paid claims describe history, not the risk of a particular address.
A regulatory floodway is a defined part of the broader floodplain with separate development constraints. Review the effective FIRM, FIS, and local ordinance before planning work near its boundary.
BFE comes from FEMA flood-hazard mapping, while design flood elevation is applied through the governing construction rules. Match both sources to the project before selecting a design number.
Locate the LiMWA to see where moderate wave action may extend landward of Zone V within a coastal A area. Its line adds wave context; local building rules still require an authority check.
Shaded and unshaded Zone X represent different mapped categories, including the 0.2-percent-annual-chance area where shown. Neither label means flooding is impossible.
Zone AH generally displays a BFE for shallow ponding. Center the correct site and record the panel, effective date, datum, and shown elevation before comparing any building measurement.
In Zone AO, the printed depth number describes average shallow-flood depth for the mapped area. Match the exact panel and legend; it is not the structure’s measured floor elevation.
When Zone A shows no BFE, search FEMA’s adopted map and study, then ask the local floodplain administrator for best available elevation data. Never estimate a controlling value from nearby labels.