What is the difference between an FHBM and a FIRM?
An FHBM is based on approximate data and identifies, in general, the SFHAs within a community. It is used in the Emergency Phase of the NFIP for floodplain management and insurance purposes. A FIRM usually is issued following a flood risk assessment conducted in connection with the community’s conversion to the Regular Phase of the NFIP. If a detailed assessment, termed a Flood Insurance Study, has been performed, the FIRM will show base flood elevations and insurance risk zones in addition to floodplain boundaries. The FIRM may also show a delineation of the regulatory floodway. (See Question 80 for a description of “regulatory floodway.”) After the effective date of the FIRM, the community’s floodplain management ordinance must be in compliance with appropriate Regular Phase requirements. Actuarial rates, based on the risk zone designations shown on the FIRM, are then applied for newly constructed, substantially improved, and substantially damaged buildings.
