The Evolution of Flood Awareness: Flood Inundation Mapping and the Next Generation of Flood Prediction Services

For decades the hydrograph has been the primary method for disseminating potential life saving river flood information to the general public. The hydrograph is a graphical representation of a single river forecast at a single point along the river, and potential impacts from the flood forecast are provided in text format to users. Advancements in hydrologic modeling, geospatial processing, and information dissemination capabilities have ushered in a new era of messaging these flood hazards to impacted communities. Flood inundation mapping transforms hydrographs and textual impacts into geolocated maps that clearly display where the flood will potentially be hazardous. This capability expands beyond individual gauge locations to visualizations of flood extents and depths along the entire river system which spans approximately 3.4 million river miles across the United States.

On September 26th, 2023, the National Weather Service began disseminating a suite of flood inundation mapping services to 10% of the nation’s population including portions of east Texas as well as for parts of the Mid-Atlantic and Northeast. This planned phased rollout of flood inundation mapping services facilitates continuous customer feedback accelerating capability enhancements while users begin to adopt and integrate these transformational mapping services from the NWS. Enhancements to accuracy, visualization techniques, impact assessments, and accessibility over the next few years will increase the value and utility of these services for communities and foster proactive decision making before, during and after flood events.

This presentation will highlight recent advancements in NWS flood inundation mapping capabilities and provide a preview of future development opportunities that will evolve this service from a new experimental product into a ubiquitous standard of utility for extreme flooding events for future decades.