What do the different flood zones mean? Flood Zone Designations

KMRD delivers risk management solutions and human capital solutions to more than 2000 clients nationwide. Learn more about us, view our client success stories, or visit our blog.

Want to talk with an expert to understand flood zones for your business? Call 866-957-5673 or send us an email.

The following table gives an explanation for the flood zone designations:

BFE = Base Flood Zone Elevation

SFHA = Land areas that are at high risk for flooding are called Special Flood Hazard Areas (SFHAs), or floodplains. These areas are indicated on Flood Insurance Rate Maps (FIRMs)

Zone	Zone Name	Description
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 O	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.
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
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.
A(1-30)	Zone A1-30	Areas subject to inundation by the 1-percent-annual-chance flood event determined by detailed methods., for which base flood elavations have been established.
V(1-30)	Zone V(1-30)	Coastal 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/AE	Zone AR/AH	An area inundated by flooding, for which BFEs or average depths have been determined.