WASHINGTON — The National Oceanic and Atmospheric Administration announced on Sept. 24 that its comprehensive flood mapping and forecasting tool has reached near-100% coverage of the United States, giving communities and emergency managers across the country access to standardized flood risk data for the first time.
The milestone is particularly significant for previously unmapped or under-mapped rural and remote areas that have lacked access to the standardized flood risk information that urban communities have relied on for years, NOAA said.
Standardized flood risk data underpins critical decisions affecting millions of Americans — from flood insurance pricing and mortgage lending requirements to local zoning decisions and emergency evacuation planning. Communities without accurate flood maps have historically faced higher insurance costs and less effective disaster preparedness.
The achievement culminates a multi-year NOAA mapping initiative that systematically expanded coverage beyond urban corridors and major river basins to include smaller watersheds, coastal areas and inland communities.
For homeowners, the expanded mapping could affect flood insurance premiums under the National Flood Insurance Program administered by the Federal Emergency Management Agency. Properties newly identified as being in flood-prone areas may face new insurance requirements, while some properties may see risk classifications change.
Local governments will also be affected. Flood maps inform land-use planning, building code requirements and infrastructure investment decisions. Communities that previously lacked detailed flood data can now incorporate standardized risk assessments into their planning processes.
The tool provides emergency managers with improved forecasting capabilities, enabling more precise evacuation orders and resource deployment during flood events. As climate-driven flooding increases in both frequency and severity across the country, accurate mapping has become increasingly critical to protecting lives and property.
NOAA’s flood mapping complements FEMA’s ongoing updates to flood insurance rate maps, which determine insurance premiums for properties in designated flood zones.