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2024 National Hydrologic Assessment

!NEW! - Flood Inundation
Mapping (FIM) Services - !NEW!

Experimental FIM services are now available for 30% of the U.S. population including Puerto Rico and the U.S. Virgin Islands. These services will be expanded to nearly 100% of the U.S. population by 2026. Experimental services depict the extent of predicted inundation, as derived from River Forecast Center forecasts and National Water Model analyses and forecasts. Services are available via the National Water Prediction Service, the NWS GIS Viewer, or directly via URLs hosted on the Hydrologic Visualization and Information Services (HydroVIS) cloud system. Additional informational resources are available below.

Public Notification Statement (PNS)
FIM Fact Sheet
Spanish Translation Dynamic FIM Services
Stage-based CatFIM Service Summary
Frequently Asked Questions (FAQs)
FIM Service Description Document (SDD)
Viewer Access Instructions
API Access Instructions
Viewing FIM in NWPS
Using CatFIM in NWPS

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Area Hydrologic Discussion

Experimental short range, episodic, discussion and graphic which highlights locations across the nation that may be impacted by rapid-onset flooding, using National Water Model and other guidance.

AHD Product Description Document
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AHD One-Pager

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Flood Hazard Outlook

High Level graphical depiction and key messages highlighting the potential threat of inland flood hazards (flash, urban, small stream and riverine) and their associated impacts (catastrophic, considerable, and limited) for the next seven days.

FHO Product Description Document
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FHO One-Pager

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National Hydrologic Discussion

Experimental discussion of the current and forecast hydrologic conditions across the nation, including a variety of short and medium range (Days 1-10) observed and modeled hydrologic guidance.

NHD Product Description Document
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NHD One-Pager

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Significant River Flood Outlook

Operational flood outlook intended to provide a general outlook for significant (moderate and above) river flooding. It is not intended to depict all areas of minor flooding or small-scale events such as localized flooding and/or flash flooding.

NWC Visualization Services

Experimental geospatial services depicting forecasts from the River Forecast Centers and the National Water Model. Services available via the prototype NWS National Map Viewer, or directly via URLs hosted on the Hydrologic Visualization and Inundation Services (HydroVIS) cloud resource.

Public Services Handbook
NWC Visualization Services Service Description Document
Provide Feedback on NWC Visualization Services