NOAA’s National Weather Service has announced that its Flood Inundation Mapping (FIM) tool, used to predict river flooding, is now available on an experimental basis to nearly 100% of the US population, up from 60% previously.
FIM produces estimates of land area covered in water based on model forecast river flows and current conditions, predicting where flooding impacts may occur in the following days. It is used by forecasters, emergency managers and the public to track river and stream flooding conditions at a neighborhood scale, covering 3.3 million river miles across the continental US, US territories and Hawaii. The latest expansion adds coverage of the southeastern US coast and Florida, the Great Lakes region, New England, the Rocky Mountains, the Dakotas and western Nebraska.
“Inundation maps are a critical tool for assessing the impacts of flooding,” said NOAA administrator Neil Jacobs, PhD. “NOAA prioritized expanding FIM to ensure that nearly every American can access detailed information beyond the expected river crest height. These maps further support NOAA’s mission to protect lives, safeguard property and strengthen our national economy.”
NWS local offices have already used FIM in emergency response. In spring 2025, the NWS office in Nashville, Tennessee used FIM to help a senior assisted living facility in Macon County safely evacuate residents hours before floodwaters arrived. In April 2025, the NWS office in Little Rock, Arkansas, shared FIM with the city of Hardy, which went door to door to evacuate residents and reported a nearly 100% success rate.
“FIM has been a game-changer when briefing emergency managers, first responders and communities facing flood risk,” said National Weather Service director Ken Graham. “It helps focus their response on the extent of flooding by using a strong and precise visualization tool.”
FIM launched in 2023 covering 10% of the US population and reached 60% coverage in 2025. The current expansion does not yet extend to northern and western Alaska, Guam, the Northern Mariana Islands or American Samoa. The maps are publicly available on the National Water Prediction Service website in several GIS file formats.
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