Zone A

The 100-year or base floodplain. There are six types of A Zones: A The base floodplain mapped by approximate methods, i.e., BFEs are not determined. This is often called an unnumbered A Zone or an approximate A Zone. Al-30 These are known as numbered A Zones (e.g., A7 or A14). This is the base floodplain where the FIRM shows a BFE (old format). AE The base floodplain where base flood elevations are provided. AE Zones are now used on new format FIRMs instead ofAI-A30 Zones. AO The base floodplain with sheet flow, ponding, or shallow flooding. Base flood depths (feet above ground) are provided. AH Shallow flooding base floodplain. BFEs are provided. A99 Area to be protected from base flood by levees or Federal Flood Protection Systems under construction. BFEs are not determined. AR The base floodplain that results from the decertification ofa previously accredited flood protection system that is in the process of being restored to provide a 100-year or greater level of flood protection.

Zone V and

V The coastal area subject to a velocity hazard (wave action) where


BFEs are not determined on the FIRM. VE The coastal area subject to a velocity hazard (wave action) where BFEs are provided on the FIRM.

Zone and Zone X (shaded)

Area of moderate flood hazard, usually the area between the limits ofthe 100-year and SOO-year floods. BZones are also used to designate base floodplains of lesser hazards, such as areas protected by levees from the 100-year flood, or shallow flooding areas with average depths of less than one foot or drainage areas less than 1 square mile.

Zone C and Zone X (unshaded)

Area ofminimal flood hazard, usually depicted on FIRMs as above the 500-year flood level Zone C may have ponding and local drainage problems that don't warrant a detailed study or designation as base floodplain. Zone X is the area determined to be outside the SOO-year flood and protected by levee from 100-year flood.

Zone D

Area ofundetermined but possible flood hazards.