FEMA’s flood maps often miss dangerous flash flood risks, leaving homeowners unprepared

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Jeremy Porter, City University of New York

(THE CONVERSATION) The deadly flash flooding in Texas and destructive flooding in states including New Mexico, Vermont and Iowa in July 2025 is raising questions about the nation’s flood maps and their ability to ensure that communities and homeowners can prepare for rising risks.

The U.S. Federal Emergency Management Agency’s flood maps are intended to be the nation’s primary tool for identifying flood risks. Originally developed in the 1970s to support the National Flood Insurance Program, these maps, known as Flood Insurance Rate Maps, or FIRMs, are used to determine where flood insurance is required for federally backed mortgages, to inform local building codes and land-use decisions, and to guide flood plain management...