Glossary of Flood Terms | Flood Zone Definitions | Availability

What do the different flood zones mean?
The following table gives an explanation of the flood zone designations used by First American Flood Data Services:

Zone Zone Name Description
  Error (Missing data) Error (Missing data).
100 Area in SFHA This is an area inundated by 100-year flooding for which BFEs or velocity may have been determined. No distinctions are made between the different flood hazard zones that may be included within the SFHA.
100IC 100-year Flood Discharge Contained in Channel An area where the 100-year flooding is contained within the channel banks and the channel is too narrow to show to scale. An arbitrary channel width of 3 meters is shown.
A Zone A An area inundated by 100 year flooding, for which no BFEs have been established.
A99 Zone A99 An area inundated by 100-year flooding, for which no BFEs have been determined. This is an area to be protected from the 100-year flood by a Federal flood protection system under construction.
AE Zone AE An area inundated by 100-year flooding, for which BFEs have been determined.
AH Zone AH An area inundated by 100-year flooding (usually an area of ponding), for which BFEs have been determined; flood depths range from 1 to 3 feet.
ANI Area Not Included An area that is located within a community or county that is not mapped on any published FIRM.
AO Zone AO An area inundated by 100-year flooding (usually sheet flow on sloping terrain), for which average depths have been determined; flood depths range from 1 to 3 feet.
AR Zone AR An area inundated by flooding, for which BFEs or average depths have been determined.
B Zone B An area inundated by 500-year flooding; an area inundated by 100-year flooding with average depths of less than 1 foot or with drainage areas less than 1 square mile; or an area protected by levees from 100-year flooding.
BE Zone BE An area inundated by 500-year flooding; an area inundated by 100-year flooding with average depths of less than 1 foot or with drainage areas less than 1 square mile; or an area protected by levees from 100-year flooding.
BL Zone B
Protected By Levee		 Areas protected from the 1% annual chance flood by levees. No Base Flood Elevations or depths are shown within this zone.
BX Zone BX An area inundated by 500-year flooding; an area inundated by 100-year flooding with average depths of less than 1 foot or with drainage areas less than 1 square mile; or an area protected by levees from 100-year flooding.
C Zone C An area that is determined to be outside the 100- and 500-year floodplains.
CE Zone CE An area that is determined to be outside the 100- and 500-year floodplains.
CX Zone CX An area that is determined to be outside the 100- and 500-year floodplains.
D Zone D An area of undetermined but possible flood hazards.
FW Floodway An area that includes the channel of a river or other watercourse (Usually adjacent to Zone AE).
FWIC Floodway Contained in Channel An area where the floodway is contained within the channel banks and the channel is too narrow to show to scale. An arbitrary channel width of 3 meters is shown. BFEs are not shown in this area, although they may be reflected on the corresponding profile
IN Area In SFHA This is an area inundated by 100-year flooding for which BFEs or velocity may have been determined. No distinctions are made between the different flood hazard zones that may be included within the SFHA.
NM Area Not Mapped An area that is located within a community or county that is not mapped on any published FIRM.
OUT Area Not Mapped An area designated as outside a "Special Flood Hazard Area" (or SFHA) on a FIRM. This is an area inundated by 500-year flooding; an area inundated by 100-year flooding with average depths of less than 1 foot or with drainage areas less than 1 square mile
OW Open Water A body of open water, such as a large pond, lake, bay, ocean, etc., located within a community's jurisdictional limits, that has no defined flood hazard.
UNDES Area of Undesignated Flood Hazard A body of open water, such as a pond, lake ocean, etc., located within a community's jurisdictional limits, that has no defined flood hazard.
V Zone V An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
VE Zone VE An area inundated by 100-year flooding with velocity hazard (wave action); BFEs have been determined.
X Zone X An area that is determined to be outside the 100- and 500-year floodplains.
X5 Zone X (500-year) An area inundated by 500-year flooding; an area inundated by 100-year flooding with average depths of less than 1 foot or with drainage areas less than 1 square mile; or an area protected by levees from 100-year flooding.
X500 Zone X (500-year) An area inundated by 500-year flooding; an area inundated by 100-year flooding with average depths of less than 1 foot or with drainage areas less than 1 square mile; or an area protected by levees from 100-year flooding.
X500IC 500-year Flood Discharge Contained in Channel An area where the 500-year flooding is contained within the channel banks and the channel is too narrow to show to scale. An arbitrary channel width of 3 meters is shown.
X500L Zone X500
Protected By Levee		 Areas protected from the 1% annual chance flood by levees. No Base Flood Elevations or depths are shown within this zone.
A1 Zone A1 An area inundated by 100 year flooding, for which no BFEs have been established.
A2 Zone A2 An area inundated by 100 year flooding, for which no BFEs have been established.
A3 Zone A3 An area inundated by 100 year flooding, for which no BFEs have been established.
A4 Zone A4 An area inundated by 100 year flooding, for which no BFEs have been established.
A5 Zone A5 An area inundated by 100 year flooding, for which no BFEs have been established.
A6 Zone A6 An area inundated by 100 year flooding, for which no BFEs have been established.
A7 Zone A7 An area inundated by 100 year flooding, for which no BFEs have been established.
A8 Zone A8 An area inundated by 100 year flooding, for which no BFEs have been established.
A9 Zone A9 An area inundated by 100 year flooding, for which no BFEs have been established.
A10 Zone A10 An area inundated by 100 year flooding, for which no BFEs have been established.
A11 Zone A11 An area inundated by 100 year flooding, for which no BFEs have been established.
A12 Zone A12 An area inundated by 100 year flooding, for which no BFEs have been established.
A13 Zone A13 An area inundated by 100 year flooding, for which no BFEs have been established.
A14 Zone A14 An area inundated by 100 year flooding, for which no BFEs have been established.
A15 Zone A15 An area inundated by 100 year flooding, for which no BFEs have been established.
A16 Zone A16 An area inundated by 100 year flooding, for which no BFEs have been established.
A17 Zone A17 An area inundated by 100 year flooding, for which no BFEs have been established.
A18 Zone A18 An area inundated by 100 year flooding, for which no BFEs have been established.
A19 Zone A19 An area inundated by 100 year flooding, for which no BFEs have been established.
A20 Zone A20 An area inundated by 100 year flooding, for which no BFEs have been established.
A21 Zone A21 An area inundated by 100 year flooding, for which no BFEs have been established.
A22 Zone A22 An area inundated by 100 year flooding, for which no BFEs have been established.
A23 Zone A23 An area inundated by 100 year flooding, for which no BFEs have been established.
A24 Zone A24 An area inundated by 100 year flooding, for which no BFEs have been established.
A25 Zone A25 An area inundated by 100 year flooding, for which no BFEs have been established.
A26 Zone A26 An area inundated by 100 year flooding, for which no BFEs have been established.
A27 Zone A27 An area inundated by 100 year flooding, for which no BFEs have been established.
A28 Zone A28 An area inundated by 100 year flooding, for which no BFEs have been established.
A29 Zone A29 An area inundated by 100 year flooding, for which no BFEs have been established.
A30 Zone A30 An area inundated by 100 year flooding, for which no BFEs have been established.
V0 Zone V0 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V1 Zone V1 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V2 Zone V2 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V3 Zone V3 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V4 Zone V4 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V5 Zone V5 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V6 Zone V6 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V7 Zone V7 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V8 Zone V8 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V9 Zone V9 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V10 Zone V10 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V11 Zone V11 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V12 Zone V12 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V13 Zone V13 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V14 Zone V14 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V15 Zone V15 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V16 Zone V16 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V17 Zone V17 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V18 Zone V18 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V19 Zone V19 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V20 Zone V20 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V21 Zone V21 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V22 Zone V22 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V23 Zone V23 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V24 Zone V24 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V25 Zone V25 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V26 Zone V26 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V27 Zone V27 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V28 Zone V28 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V29 Zone V29 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
V30 Zone V30 An area inundated by 100-year flooding with velocity hazard (wave action); no BFEs have been determined.
Z Area of Unknown Flood Hazard An area of Data Discrepancy or an Unclaimed Area. Internal TFHC designation.
N Area Not Mapped An area that is located within a community or county that is not mapped on any published FIRM (Usually a community not participating in NFIP). Internal TFHC designation.
AR/A Zone AR/A An area inundated by flooding, for which BFEs or average depths have not been determined.
AR/AE Zone AR/AE An area inundated by flooding, for which BFEs or average depths have been determined.
AR/AH Zone AR/AH An area inundated by flooding, for which BFEs or average depths have been determined.
 

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