Area flood occurrence and recurrence patterns

Versioned multi-decade three-hourly ponded-water grids support thresholded modeled recurrence under explicit geometry/window/version; they are reconstructions, not observations.

Open NWS Flood and Flash Flood records supply time, event identity, cause, linked locations, reporting source, and revisions, supporting reported occurrence patterns but not inundation depth or probability.

The public API returns NFIP flood-claim transactions with date of loss, named flood event when populated, and state, ZIP, county, census GEOID, and rounded coordinates; exact event-name and county-code filters returned unrelated records through the standing unauthenticated service. Those records provide supplemental evidence of when and where insured flood losses were reported and can support an explicitly claim-reported recurrence history for a defined area and window. Claim presence is not a complete flood-occurrence inventory and supplies no exposure denominator; do not treat the evidence as building-specific through containment or use water-depth fields as severity until units and semantics are documented. Preserve the geographic boundary, claim-event definition, observation window, NFIP coverage basis, and dataset as-of date.