WASHINGTON, D.C. — The National Weather Service has expanded its Flood Inundation Mapping (FIM) services to cover nearly 100 percent of the U.S. population, marking a major milestone in how Americans can understand river flood risk.
The latest expansion adds the East Coast, the Great Lakes region, the Rocky Mountains, and the northern Plains. FIM now shows the geographic extent of projected river flooding for more than 3.3 million river miles across the United States and its territories.
What Flood Inundation Mapping Actually Shows
Traditional river forecasts tell people how high a river is expected to rise at a specific gauge. That number, however, does not always explain what it means on the ground for a home, a street, or a neighborhood.
Flood Inundation Mapping fills that gap by visually displaying where water is projected to spread when rivers rise. Instead of just seeing a river stage number, residents can look at a map and see which areas could end up underwater.
For families living near a creek, river, or floodplain, this turns a technical forecast into something easy to understand and act on.
Nationwide Rollout Completed in Four Phases (2023-2026)
The NWS Flood Inundation Mapping Services map shows the rollout happened in stages over four years, from 2023 through 2026.
2023 (Phase 1): Texas among the first areas to receive the service
2024 (Phase 2): Large portion of the South and Mid-South, including:
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Missouri
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Arkansas
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Louisiana
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Mississippi
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Alabama
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Tennessee
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Kentucky
2025 (Phase 3): Extended service into:
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Kansas
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Iowa
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Oklahoma
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New Mexico
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California
2026 (Phase 4 – Final): Completed the national picture
2026 Expansion: Rockies, Northern Plains, Great Lakes, and East Coast
The final 2026 phase completed coverage across the country:
Rocky Mountains:
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Montana
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Idaho
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Wyoming
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Utah
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Colorado
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Nevada
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Arizona
Northern Plains:
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North Dakota
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South Dakota
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Critical for spring snowmelt and river flooding along the Red River and Missouri River basins
Great Lakes Region:
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Wisconsin
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Michigan
East Coast:
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Maine
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North Carolina
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South Carolina
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Georgia
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Florida
Alaska: Also covered in 2026 phase
Hawaii, Puerto Rico, and U.S. Virgin Islands Included
The service is not limited to the lower 48 states. The map also includes:
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Hawaii
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Alaska
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Puerto Rico
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U.S. Virgin Islands
This reflects comprehensive coverage across the United States and all its territories.
For island communities, where steep terrain can send heavy rain rushing into streams within minutes, having a clear visual of projected flooding can be especially valuable.
Why This Matters for Local Communities
River flooding remains one of the most common and costly weather hazards in the country. Many people underestimate their risk because they cannot picture how far water might spread beyond a river’s normal banks.
With FIM, residents can:
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Check whether their home falls within a projected flood zone
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See if their workplace, school, or daily commute is at risk
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Decide when to move vehicles before flooding begins
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Protect belongings or evacuate early
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Plan ahead with confidence
Local emergency managers, first responders, and city officials can also use the maps to:
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Plan road closures before water arrives
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Organize evacuations more efficiently
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Position resources strategically ahead of flooding
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Communicate risk more clearly to residents
How Residents Can Use the New Maps
The maps are available through water.noaa.gov/fim, where users can explore projected flooding in their area.
Best practices:
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Check the map alongside official Flood Watches and Flood Warnings
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Look up your area now, before any flood threat develops
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Know whether your neighborhood sits in a flood-prone zone
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Plan evacuation routes in advance
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Prepare an emergency kit ahead of time
When a river flood threat develops, using FIM gives a much clearer picture of what to expect compared to traditional gauge readings alone.
Flood Safety Still Starts With Official Alerts
Maps are a powerful tool, but they work best alongside official warnings. Residents should always follow instructions from the National Weather Service and local officials during flood events.
Critical safety reminders:
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Never drive or walk through flooded roads
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Just a few inches of moving water can knock a person off their feet
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Slightly deeper water can carry away a vehicle
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When in doubt: Turn Around, Don’t Drown
The Bottom Line
With this expansion complete, nearly every American now has access to a clearer picture of how rising rivers could affect the places they live and travel.
Whether you’re in Texas (covered since 2023), the Great Lakes region (added in 2026), or an island community in Hawaii or Puerto Rico, Flood Inundation Mapping puts critical flood risk information at your fingertips.
Take action today:
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Visit water.noaa.gov/fim
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Search for your address or neighborhood
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Save the map link for quick access during flood season
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Share with family members who live in flood-prone areas
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Include FIM in your emergency preparedness planning
The era of guessing about flood risk is over. Now, every American can see exactly where water is projected to spread—before it happens.
