An official revision of a current Flood Insurance Rate Map (FIRM) accepted by FEMA, which reflects changes in mapped areas for flood zones, floodplain areas, floodways and flood elevations.
a LOMR is an official revision to the current effective FEMA map. It is used to change flood zones, floodplain and floodway delineations, flood elevations, and other features. A LOMR is usually followed by a physical map revision.
Letter of Map Revision. An official amendment to the currently effective FEMA map. It is issued by FEMA and changes flood zones, delineations, and elevations.