F.E.M.A. Flood Zone Designations & Explanations


Flood Zone Tables:

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Annual Probability of Flooding of 1% or greater
Zone Designations & Explanations
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 poundings) 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.
V Subject to 100-year flood and additional velocity hazard (wave action). Base flood elevation undetermined.
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 An area designated as a "Flood Prone Area" on a map prepared by USGS and the Federal Insurance Administration. 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.

Annual Probability of Flooding of 0.2% to 1%
Zone Designations & Explanations
B or X500 Both B and X500 represent areas between the limits of the 100-year and 500-year flood; or 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.

Annual Probability of Flooding of Less than 0.2%
Zone Designations & Explanations
C or X Both C and X represent areas outside the 500-year flood plain with less than 0.2% annual probability of flooding.

Annual Probability of Flooding of Less than 1%
Zone Designations & Explanations
No SFHA Areas outside a "Special Flood Hazard Area" (or 100-year flood plain). Can include areas inundated by 0.2% annual chance flooding; areas inundated by 1% annual chance flooding with average depths of less than 1 foot or with drainage areas less than 1 square mile; areas protected by levees from 1% annual chance flooding; or areas outside the 1% and 0.2% annual chance floodplains.

Undetermined
Zone Designations & Explanations
D Unstudied areas. Flood hazards are undetermined.

Information provided by Palm Beach County