Glossary
FEMA and flood map terminology in plain English.
The glossary is written to help users understand the terms that show up in flood determinations, lender notices, surveys, and map-change workflows.
Glossary
Base Flood Elevation
The elevation benchmark used when evaluating flood map change requests and floodplain context.
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Special Flood Hazard Area
The mapped flood hazard area that often triggers mandatory flood insurance requirements.
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Flood Insurance Rate Map
The FEMA map used to show flood zones and related floodplain designations.
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National Flood Hazard Layer
FEMA's national flood hazard dataset that can be used to enrich property and community context.
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Zone A
A mapped flood zone designation that often appears on flood determinations and insurance paperwork.
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Zone AE
A common FEMA flood zone designation that often pairs with Base Flood Elevation data.
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Zone VE
A coastal flood zone designation that requires careful explanation when it appears in a property file.
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Floodway
A mapped floodplain concept that can materially affect the complexity of a flood map change discussion.
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Elevation Certificate
A common technical document used in flood map review, insurance, and floodplain administration workflows.
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Letter of Map Amendment (LOMA)
A LOMA is FEMA's official determination that a property sits on natural high ground above the Base Flood Elevation.
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Letter of Map Revision (LOMR)
A LOMR is FEMA's official revision to a flood map, changing flood zone boundaries or Base Flood Elevations.
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Letter of Map Revision Based on Fill (LOMR-F)
A LOMR-F is FEMA's determination that a property elevated by fill material is now above the Base Flood Elevation.
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Conditional Letter of Map Amendment (CLOMA)
A CLOMA is FEMA's preliminary determination that a proposed project on natural high ground would qualify for a LOMA.
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Conditional Letter of Map Revision Based on Fill (CLOMR-F)
A CLOMR-F is FEMA's conditional determination that a proposed fill project would qualify for a LOMR-F once completed.
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Online LOMC (Letters of Map Change Portal)
FEMA's online portal for submitting and tracking Letters of Map Change applications digitally.
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Electronic Letter of Map Amendment (eLOMA)
An eLOMA is a faster LOMA pathway where a licensed surveyor submits and receives a determination electronically.
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National Flood Insurance Program (NFIP)
The NFIP is the federal program that provides flood insurance to property owners in participating communities.
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Zone X
Zone X is a FEMA flood zone designation for areas with moderate to minimal flood risk, outside the high-risk SFHA.
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Community Rating System (CRS)
The CRS is a FEMA program that rewards communities with flood insurance premium discounts for exceeding minimum floodplain management standards.
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Flood Determination
A flood determination is the process lenders use to check whether a property falls inside a FEMA Special Flood Hazard Area.
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Lowest Adjacent Grade (LAG)
Lowest Adjacent Grade is the lowest ground elevation touching a building's exterior, a critical measurement in LOMA applications.
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Lowest Floor Elevation
The lowest floor elevation is the elevation of a building's lowest floor, critical for flood insurance rating and Elevation Certificates.
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Letters of Map Change (LOMC)
LOMC is FEMA's umbrella term for all official documents that change or amend a flood map, including LOMAs, LOMRs, and LOMR-Fs.
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Preferred Risk Policy (PRP)
A Preferred Risk Policy is a lower-cost NFIP flood insurance option available to properties in moderate- to low-risk flood zones.
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Risk Rating 2.0
Risk Rating 2.0 is FEMA's updated methodology for calculating NFIP flood insurance premiums based on individual property risk.
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FIRMette
A FIRMette is a printable, zoomed-in excerpt from a FEMA Flood Insurance Rate Map centered on a specific property or area.
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Map Information eXchange (MIX)
FEMA MIX is a query system that provides access to flood map data, community information, and map change records.
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