National Flood Hazard Boundaries for US States and Territories

Flood hazard boundaries incorporate all Digital Flood Insurance Rate Map databases and subsequent map revisions published by the Federal Emergency Management Agency. The data includes primary risk classifications for the 1-percent and 0.2-percent annual chance flood events, derived from Flood Insurance Studies and analyses. It is maintained by the Earth Data Analysis Center at the University of New Mexico.

Use Cases

• Map 1-percent-annual-chance flood event zones for property risk assessment and insurance modeling.
• Analyze 0.2-percent-annual-chance flood event boundaries for extreme flood scenario planning.
• Identify areas of minimal flood risk to support land-use and urban development decisions.
• Cross-reference Digital Flood Insurance Rate Map data with Letters Of Map Revision to track regulatory changes.

Strengths

• Data incorporates all published Digital Flood Insurance Rate Map databases and subsequent revisions.
• Horizontal control specifications are consistent with mapping at a scale of 1:12,000.
• Available as comprehensive State or US Territory datasets covering all available DFIRMs.

Limitations

• The last update was in December 2020, making the data potentially stale for recent flood hazard changes.
• Sample data and specific row/column counts are unavailable, limiting pre-download assessment of structure.
• The description notes the dataset excludes specific layers like S_Label_Pt and S_Label_Ld.

Provenance

Source

Federal Emergency Management Agency (FEMA) via the Earth Data Analysis Center, University of New Mexico.

Collection Method

Derived from Flood Insurance Studies, previously published Flood Insurance Rate Maps, flood hazard analyses, and new mapping data.

Freshness

Last updated 2020-12-02.

Geography

United States, available as State or US Territory datasets.