Flood Insurance Rate Map - an official map created by FEMA that shows flood risk zones, base flood elevations, and floodplain boundaries for a community. FIRMs are used to determine flood insurance requirements and premium rates under the National Flood Insurance Program. These maps identify Special Flood Hazard Areas where flood insurance is mandatory for federally backed mortgages. Property owners can use FIRMs to understand their flood risk and make informed decisions about insurance coverage and property improvements. Maps are periodically updated as flood risk data changes.