Weather
U.S. Flood Mapping Expands Today to Nearly 100% of Nation
United States – Americans now have access to detailed flood mapping covering nearly the entire U.S. population, giving communities another tool to see where river flooding could spread before and duri
By Tessa Morgan · 2026-09-24T15:58:30.430Z
United States – Americans now have access to detailed flood mapping covering nearly the entire U.S. population, giving communities another tool to see where river flooding could spread before and during dangerous weather events.
According to NOAA, the National Weather Service announced Thursday that its experimental Flood Inundation Mapping system, known as FIM, has expanded from coverage of about 60% of the country to nearly 100%.
The technology uses river forecasts and current conditions to estimate the amount of land that could be covered by water. Unlike traditional river forecasts that focus primarily on water levels at specific gauges, the maps can show the potential geographic extent and depth of flooding.
NOAA said the system now depicts flooding potential along approximately 3.3 million river miles throughout the continental United States, U.S. territories and Hawaii.
Recent expansion added areas including southeast Florida, the Great Lakes region, New England, the Rocky Mountains, the Dakotas and western Nebraska.
The agency said the technology has already been used during real world emergencies. National Weather Service offices have provided FIM data to emergency managers making evacuation and road closure decisions during flooding in Tennessee, Arkansas, Texas, Louisiana, Oklahoma and Michigan.
FIM initially launched in 2023 with coverage for approximately 10% of the U.S. population before expanding to 60% in 2025.
The maps are available through the National Weather Service and provide current condition analyses along with forecasts showing potential inundation over coming days.
NOAA emphasized that the system remains experimental as forecasters continue improving the technology.