National Flood Hazard Layer Data for United States

December 2020 data from the Federal Emergency Management Agency (FEMA) incorporates Digital Flood Insurance Rate Map (DFIRM) databases and subsequent Letters Of Map Revision (LOMRs). The dataset provides geospatial flood hazard information, including primary risk classifications like the 1-percent-annual-chance flood event. It is derived from Flood Insurance Studies and mapping data, with horizontal control specifications for mapping at a scale of 1:12,000.

Use Cases

• Analyze spatial patterns of the 1-percent-annual-chance flood event and 0.2-percent-annual-chance flood event classifications to model flood risk.
• Integrate Digital Flood Insurance Rate Map (DFIRM) data with Letters Of Map Revision (LOMRs) to track changes in designated Special Flood Hazard Areas (SFHA).
• Use the Coastal Barrier Resources System (CBRS) layer alongside flood hazard zones for environmental planning and regulatory compliance assessments.
• Process geospatial data conforming to a 1:12,000 scale specification for high-resolution floodplain mapping and infrastructure planning.

Strengths

• Data incorporates all published DFIRM databases and subsequent Letters Of Map Revision (LOMRs), ensuring regulatory comprehensiveness.
• Horizontal control specifications are consistent with mapping at a detailed scale of 1:12,000.
• Covers the United States and its territories, organized as State or US Territory datasets.

Limitations

• Data is not current, with a last update recorded in December 2020, potentially missing recent flood map revisions.
• Specific data volume metrics such as row count, file size, and column structure are unknown.
• The dataset excludes the S_Label_Pt and S_Label_Ld layers found in Standard DFIRM datasets.

Provenance

Source

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

Collection Method

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

Time Range

Publication date of the dataset is 2020-12-02; specific temporal coverage of the underlying maps is not specified.

Freshness

Last updated 2020-12-02; update frequency is unknown.

Geography

United States and its territories, available as State or US Territory datasets.