FEMA Flood Zones
Flood 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.
Zone Designation | Description | Risk Category | Event Likelihood | Elevation Shown |
A | High risk of flooding due to ponds, streams, or rivers. | High | > 1% (< 100-year) | No |
AE | High risk of flooding due to ponds, streams, or rivers. | High | > 1% (< 100-year) | Yes |
A1-30 | High risk of flooding due to ponds, streams, or rivers (old format). | High | > 1% (< 100-year) | Yes |
AH | Shallow flooding ranging from 1 to 3 feet, usually in the form of a pond. | High | > 1% (< 100-year) | Yes |
AO | River or stream flood, with an average depth ranging from 1 to 3 feet. | High | > 1% (< 100-year) | No, Avg Depth only |
AR | Temporarily increased flood risk due to building or restoration of a flood control system. | High | > 1% (< 100-year) | No |
A99 | Protected by a Federal flood control system where construction has reached specified legal requirements. | High | > 1% (< 100-year) | No |
V | Coastal flooding due to storm surge waves, sea level rise, or coastal subsidence. Depth or base flood elevations unknown. | High | > 1% (< 100-year) | No |
VE | Coastal flooding due to storm surge waves, sea level rise, or coastal subsidence. Depth or base flood elevations provided (new format). | High | > 1% (< 100-year) | Yes |
V1-30 | Coastal flooding due to storm surge waves, sea level rise, or coastal subsidence. Depth or base flood elevations provided (old format). | High | > 1% (< 100-year) | Yes |
B | Area between the limits of the 100‐year and 500‐year floods, levee-protected areas, shallow flooding < 1 foot, or drainage areas < 1 square mile. | Moderate | 0.2~1% (100~500-year) | Unknown |
C | May have ponding or local drainage problems that don't warrant detailed study. | Minimal | < 0.2% (> 500-year) | Unknown |
X | Determined to be outside the 500-year flood and protected by level from the 100-year flood (See note below). | Low | < 0.2% (> 500-year) | Unknown |
D | Possible but undetermined flood hazards. | Unknown | N/A | No |
Note: The flood zone X documentation ambiguously conflates it with zones B and C. Further investigation into the data may be required.
Key Data Sources: