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Catalog datasets represent a fraction of data in use by active WMA projects. The team is working on including more datasets to provide a complete view of data-in-use. Let us know how your experience is!

Datasets

National Flood Hazard Layer

Domain: Hydrology; Stream Characteristics

Variables:
▶ FEMA flood hazard zones; River mile markers; Cross-section and coastal transect locations; Letter of Map Revision boundaries and case numbers; FIRM boundaries/labels/effective dates;
See 7 More Variables...

Spatial Resolution: 1:50,000; 1:250,000

Temporal Frequency: daily

Temporal Coverage: 2025

Spatial Extent: CONUS; AK; HI

Source: FEMA

Update Type: Dynamic

Update Frequency: daily

Update Detail: append

Access:

Description:

The National Flood Hazard Layer (NFHL) dataset represents the current effective flood data for the country, where maps have been modernized. It is a compilation of effective Flood Insurance Rate Map (FIRM) databases and Letters of Map Change (LOMCs). The NFHL is updated as studies go effective.