NWS Flood Inundation Mapping: Roles and Experiences at River Forecast Centers

The National Weather Service (NWS) continues to expand flood inundation mapping (FIM) capabilities across the nation. The rollout is occurring in annual phases, gradually expanding into different regions of the United States, eventually covering 100% of the population by 2026. FIM serves as a powerful tool for visualizing and communicating flood forecasts, impacts, and risks, particularly in areas where such resources have not been available across the nation.

As an essential component of successful FIM operational implementation, NWS field forecast offices, including River Forecast Centers (RFC), are assisting with preparations and developing best practices and strategies for incorporating FIM into flood forecasting and outreach. NWS RFCs, as offices specializing in operational hydrology, play a pivotal role with training, outreach, and evaluation of FIM resources to benefit forecasters, the public, and interagency core partners.

This presentation showcases the experiences and activities over the past two years at the NWS Middle Atlantic River Forecast Center (MARFC), as one of the “10% phase” offices, summarizing the efforts undertaken to prepare and adopt the new FIM capabilities. Examples from facilitating training with forecasters, evaluating FIM quality and flood impacts, and promoting FIM availability and engagement across partner agencies, demonstrate some success stories and lessons learned to benefit the FIM rollout process, as it continues through 2026.

The goal of the presentation is to demonstrate some ideas of how to introduce the new FIM capabilities to NWS forecast offices and their partners, showcasing the strengths and limitations, and demonstrating the benefits of FIM as a new, but critical tool for flood forecasting and hazard communication.