NFIP Flood Zone Explanations

NFIP FLOOD ZONE EXPLANATIONS

(January 2019)

 

The National Flood Insurance Program (NFIP) uses a zoning system for assigning an area’s vulnerability to flood losses. Here is an explanation of the flood zone designations used by the NFIP and FEMA:

 

 

NFIP FLOOD ZONES

Zone

High Risk Areas

A

Subject to 100-year flood. Base flood elevation undetermined.

AE or A1-A30

Both AE and A1-A30 represent areas subject to 100-year flood with base flood elevation determined.

AH

Subject to 100-year shallow flooding (usually areas of ponding) with average depth of 1-3 feet. Base flood elevation determined.

AO

Subject to 100-year shallow flooding (usually sheet flow on sloping terrain) with average depth of 1-3 feet. Base flood elevation undetermined.

A99

Subject to 100-year flood, with federal flood protection system (levee/dam) under construction. Base flood elevation undetermined.

AR

Previously accredited flood protection system has been decertified and is in the process of being restored to provide a 100-year or greater level of flood protection.

V

Subject to 100-year flood and additional velocity hazard (wave action). Base flood elevation undetermined.

Zone

High Risk – Coastal Areas

VE or V1-V30

Both VE and V1-V30 represent areas subject to 100-year flood and additional velocity hazard (wave action). Base flood elevation determined.

In SFHA

Areas in a "Special Flood Hazard Area" (or 100-year flood plain). Subject to 1% annual chance flooding. No distinctions have been made between the different flood hazard zones that may be included within the SFHA.

Flood Prone Area

This area has been delineated based on available information on past floods. This is an area inundated by 1% annual chance flooding for which no base flood elevations have been determined.

Zone

Moderate to Low Risk Areas

B or X (shaded)

Both B and X500 represent areas between the limits of the 100-year and 500-year flood. It also applies to certain areas subject to 100-year flood with average depths less than 1 foot or where the contributing drainage area is less than 1 square mile; or areas protected by levees from the 100-year flood.

C or X (unshaded)

Both C and X represent areas outside the 500-year flood plain with less than 0.2% annual probability of flooding

Zone

Undetermined Risk Area

D

Unstudied areas. Flood hazards are undetermined.