Do You Know Your FEMA Flood Zones?

I thought I’d post the different flood risk zone designations used by FEMA on their FIRM maps. These are used for your flood insurance calculations. I’ll have more on the risk to flood events for Hawaii’s residents down the road since I used to study coastal hazards way back when, but here’s a quick list of the FEMA zones. For more info on Hawaii’s participation in the National Flood Insurance Program, go HERE.

Understanding FEMA Flood Zones and Insurance

To categorize flood risk at varying levels, FEMA has identified geographic areas as flood zones. These areas are noted on a Flood Insurance Rate Map (FIRM) and/or Flood Hazard Boundary Map (FHBM). These maps show the types of flooding and severity across a landscape. If the local community participates in the National Flood Insurance Flood Program (NFIP) as indicated on the FIRM, all homeowners and renters are eligible for flood insurance. It is a good idea that residents who live in high risk areas have a basic understanding of how to read these maps since flood zones are defined to help homeowners figure out the type of flood insurance they will need to purchase.

Moderate to Low Risk Areas

• These areas are identified as B and X shaded zones and C and X unshaded zones in communities that participate in the NFIP. Flood insurance is available for all persons living in these zones.

• B and X shaded zones are usually between the limits of 100-year and 500-year floods.

• C and X unshaded zones are above the 500-year flood level as depicted on the FIRM and is an area of minimal flood damage.

High Risk Areas

• Flood insurance is required of all residents living in communities that participate in the NFIP.

• Zone A – Over the term of a 30-year mortgage, these areas have a 26% likelihood of experiencing a flood event.

• Zone AE provides base flood elevations in the floodplain for the new FIRM format. This new designation replaces the old A1 to A30 zone numbering system.

• Zones A1 to A30 are no longer used on FIRMs to indicate the floodplain.

• Zone AH – Over the time of a 30-year mortgage these areas have a 26% chance of shallow flooding in the form of a pond ranging anywhere from 1 to 3 ft. The annual chance of a flood event is 1%.

• Zone AO designates hazard areas for river or stream flooding. Over the existence of a 30-year mortgage there is a 26% probability of flooding from a depth ranging anywhere from 1 to 3 ft.

• Zone AR includes areas that are increasingly vulnerable to a flood event due to construction or restoration of a system used for flood control (levee or dam).

• Zone A99 indicates an area that is protected by the Federal flood control system. Construction has reached legal requirements and there is less than a 1% chance of annual flooding.

High Risk Coastal Areas

• Flood insurance is mandatory for all residents in these zones if their community participates in the NFIP.

• Zone V has a 1% annual danger of flooding due to storm waves. No elevations are shown on the map.

• Zone VE, and V1 to V30 have a greater than 1% chance of flooding from storm waves. Detailed elevation analyses are shown on the map.

Undetermined Risk Areas

• Zone D has never had a flood analysis done and it is undetermined what the risk is of a flood event. Insurance rates reflect this uncertainty.