National Weather Service Flood Inundation Mapping expands to 60% of U.S. population

SOUTH CHARLESTON, W.Va. (WOWK) – In 2023, the National Weather Service rolled out a new weather model specifically designed to help forecast flood impact zones along streams, creeks, rivers and other bodies of water.

Known as Flood Inundation Mapping (FIM), the roll out began in New England and sections of Texas in late 2023, covering about 10% of the U.S. population. In October 2024, more areas were added, including West Virginia, Ohio and Kentucky.

The National Weather Service announced that, as of September 3, 60% of the U.S. population has been added to the FIM model service. The complete roll out for the entire nation is expected to be done by late 2026.

What is Flood Inundation Mapping?

The National Weather Service and the National Water Prediction Service collects data on thousands of rivers in a multitude of spots that they use to plot on hydrographs. A great resource if you happen to live near one of these data points or river gauges like the one located on the Ohio River in Huntington.

They do have their limitations and rely heavily on eyewitness reports of past floods to help give reference to what “moderate flooding” of 55 feet really means for Huntington and towns down river.

Flood Inundation Mapping is an experimental forecasting service that looks to not only point to a river and call for flood potential, but to map out where the water will go.

Looking at flow rates and depth of rivers both present and past, topography of the land the river flows through, rainfall rates expected or occurring, snowmelt estimates and more — the National Weather Service is able to show what areas will flood, with successful executions already under their belt since the 2023 rollout.

Some uses were in West Virginia, with the Mud River flood in 2024 and the 2025 Tug Fork River flood in Kentucky.

The image above is from the Flood Inundation Mapping output showing areas along the Tug Fork River in Warfield, Kentucky that could flood as the river reached historic flood stage. Local emergency teams used those maps to deploy the National Guard with high-water vehicles directly to the right neighborhoods, evacuating all residents before water entered the apartments.

With a few events since the 2024 roll out for the National Weather Service Office in Charleston, Senior Service Hydrologist Nick Webb was able to view the forecast alongside actual photos before, during and after flooding.

The results spoke for themselves as he showed StormTracker 13 Meteorologist Bradley Wells the side by side comparisons.

Not only was the system able to pinpoint areas that would flood, but to the extent of which lane of a two-lane road would be water covered. Matching the forecast to the actual event in impressive detail.

While the system is still experimental, its use has been combined with several other methods, models and forecast knowledge to build a better defense again flooding across the country.

In 2024 alone, 166 people died in flooding events with over $187 billion in damages often covered by FEMA, local governments and individuals with lacking flood insurance.

The tool looks to predict a flood days out and tries to pinpoint the floods reach to the exact address on a map, lowering both the economic impact and the human lives lost in flooding events.

To see the consumer side in action, the National Weather Service made public sections of the FIM data maps which can be found by visiting your local National Weather Services website.

For our region, you can visit:

Charleston, West Virginia | Jackson, Kentucky | Blacksburg, Virginia | Wilmington, OH | Pittsburg, PA