What are flood maps?
To prepare the flood maps that illustrate the extent of flood hazard in a flood prone community, FEMA generally conducts engineering studies referred to as Flood Insurance Studies (FISs). Using the information gathered in these studies, FEMA engineers and cartographers delineate Special Flood Hazard Areas (SFHAs) on Flood Maps, Special Flood Hazard Areas are subject to inundation by a flood that has a 1-percent or greater chance of being equaled or exceeded during any given year. This type of flood commonly is referred to as the 100-year flood or base flood.
“Flood maps” refers to the over 100,000 Flood Insurance Rate Maps (FIRMs) FEMA has produced for communities throughout the country. These maps serve many purposes, notably to identify the flood risk of a property or structure. Maps typically designate high-risk flood areas with shaded colors. Some of the earliest maps were produced in the early 70’s, and most urban areas have them continuously updated every few years with more precise data and detail. The statutory authority of these maps is far-reaching; they are usually the basis on community development, floodplain management, and insurance needs for homeowners.
Flood Maps provide flood risk information for a community. Any land area susceptible to being inundated by flood waters is identified as a floodplain on the maps. A Flood Insurance Rate Map (FIRM) is the official map of a community on which the Federal Emergency Management Agency (FEMA) has identified both the special flood hazard areas and the flood risk premium zones applicable to the community. All areas of the city have not been mapped and there are areas that are susceptible to flooding that are not identified on FEMA maps.
