A Flood Insurance Rate Map (FIRM) is an official map on which FEMA has delineated Special Flood Hazard Area (SFHAs) applicable to the community. As part of its Risk MAP effort, FEMA scientists and engineers work with other federal, state, regional, community, tribal, non-profit, nongovernmental and private-sector partners to determine the flood risk for properties along the populated U.S. coastline. If you live in a populated area along the coast, your community may have recently received, or may soon receive, an updated coastal FIRM and Flood Insurance Study report.
Zone VE and Zone AE
Within a coastal SFHA are two primary flood hazard zones: Zone VE and Zone AE. Zone VE, also known as a Coastal High Hazard Area, is considered one of the areas of highest risk depicted on FIRMs. Zone VE is designated where wave hazards are expected to be particularly strong and have the potential to cause dramatic structural damage. To address the added wave hazard, more stringent building practices are required in Zone VE, such as elevating a home on pilings so that waves can pass beneath it, or a prohibition to building on fill, which can be easily washed away by waves. These practices are intended to improve the chance of a home safely weathering a storm.
Base Flood Elevations (BFEs) will vary in each zone. Changes in flood zones and BFEs can have a significant impact on building requirements and flood insurance costs. BFEs may differ dramatically within a small area, because waves can diminish in size over a short distance upon encountering obstructions or steep ground.
Limit of Moderate Wave Action (LiMWA)
The coastal areas designated as Zone AE are places that experience lesser wave conditions during storm events, compared to Zone VE, or areas that are well sheltered from waves. Some Zone AE areas also have a Limit of Moderate Wave Action (LiMWA) shown on the FIRM; this is the location where the 1-percent-annual-chance wave height equals 1.5 feet. Past storms have shown that waves as small as 1.5 feet can cause foundation failure and structural damage to buildings.
To communicate the high risk from waves that still exists in a portion of the Zone AE areas, FEMA began showing the LiMWA on FIRMs. Communities are encouraged to adopt building construction standards similar to Zone VE in those areas.
Flooding occurs not only in Special Flood Hazard Areas, such as Zones AE and VE, but also in areas with a low to moderate hazard, shown as Zone X on a FIRM. Anyone can be financially vulnerable to floods. People outside of high-risk areas file over 20 percent of National Flood Insurance Program claims and receive one third of FEMA’s disaster assistance for flooding.
Throughout the lifecycle of each coastal flood risk study, FEMA encourages community and public involvement and feedback. The regulatory requirements for coordination with community officials, including the appeal process, are documented in the Code of Federal Regulations at Title 44, Chapter I, Parts 66 and 67.
Map Revisions or Amendments
After a FIRM has been adopted, there are several processes available to revise or amend the map to accommodate map scale limitations or manmade or natural changes in floodplains.
Next: Coastal Flood Insurance Studies