Flood Zones 101Flood zones are geographic areas that the FEMA has defined according to varying levels of flood risk. These zones are depicted on a community's Flood Insurance Rate Map (FIRM) or Flood Hazard Boundary Map. Each zone reflects the severity or type of flooding in the area.
Flood hazard areas identified on the Flood Insurance Rate Map are identified as a Special Flood Hazard Area (SFHA). SFHA's are defined as the area that will be inundated by the flood event having a 1-percent chance of being equaled or exceeded in any given year. The 1-percent annual chance flood is also referred to as the base flood or 100-year flood. SFHAs are labeled as Zone A, Zone AO, Zone AH, Zones A1-A30, Zone AE, Zone A99, Zone AR, Zone AR/AE, Zone AR/AO, Zone AR/A1-A30, Zone AR/A, Zone V, Zone VE, and Zones V1-V30 Moderate flood hazard areas, labeled Zone B or Zone X (shaded) are also shown on the FIRM, and are the areas between the limits of the base flood and the 0.2-percent-annual-chance (or 500-year) flood. The areas of minimal flood hazard, which are the areas outside the SFHA and higher than the elevation of the 0.2-percent-annual-chance flood, are labeled Zone C or Zone X (unshaded). FEMA FLOOD ZONES B, C and X - These areas have been identified in the community FIS as areas of moderate or minimal hazard from the principal source flood in the area. However, buildings in these zones could be flooded by severe, concentrated rainfall coupled with inadequate local drainage systems. Local storm water drainage systems are not normally considered in the communities FIS. The failure of a local drainage system creates areas of high flood risk within these rate zones. Flood insurance is available in participating communities. (Zone “X” is used on new and revised maps in place of Zones B and C.) D - Unstudied areas where flood hazards are undetermined but flooding is possible. Flood insurance is available in participating communities. V - SFHA’s along coasts subject to inundation by the 100-year flood with the additional hazards associated with storm waves. Because detailed hydraulic analyses have not been performed, no base flood elevations or depths are shown. VE & V1-V30 - SFHA’s along coasts subject to inundation by the 100-year flood with the additional hazards due to velocity (wave action). Base flood elevations derived from detailed hydraulic analyses are shown within these zones. (Zone VE is used on new and revised maps in place of zones V1-V30.) A - SFHA’s subject to inundation by the 100-year flood. Because detailed hydraulic analyses have not been performed, no base flood elevations or depths are shown. AE & A1-A30 - SFHA’s subject to inundation by the 100-year flood determined in a FIS by detailed methods. Base flood elevations are shown within these zones. (Zone AE is used on new and revised maps in place of zones A1-A30.) AH - SFHA’s subject to inundation by 100-year shallow flooding (usually areas of ponding) where average depths are between one and three feet. Base flood elevations derived from detailed hydraulic analyses are shown within these zones. AO - SFHA’s subject to inundation by 100-year shallow flooding (usually sheet flow on sloping terrain) where average depths are between one and three feet. Average flood depths derived from detailed hydraulic analyses are shown within these zones. A99 - SFHA’s subject to inundation by the 100-year flood, which will be protected by a federal flood protection system when construction has reached specified statutory progress toward completion. No base flood elevations or depths are shown. Get Your Flood Zone Determination, FEMA Flood Map or Flood Insurance Dispute FEMA ACRONYMS SFHA - Special Flood Hazard Area NSFHA - No Special Flood Hazard Area FIS - Flood Insurance Study BFE - Base Flood Elevation FIRM - Flood Insurance Rate Map FEMA - Federal Emergency Management Agency NFIP - National Flood Insurance Program 100-year flood - The floodplain associated with a flood that has a 1-percent-annual chance of being equaled or exceeded in any given year. Therefore, the SFHA is not a flood event that happens once in a hundred years, rather a flood event that has a one percent chance of occurring every year |