Evaluation of the NC-CERA Storm Surge and Wave Visualization Tool by Emergency Managers

Storm surge and wave forecasts during tropical events are critical to the emergency management (EM) community in North Carolina's coastal and river surge counties. Although many operational decisions made by EM in these counties are based on the onset time of tropical storm force winds, surge and wave information can give EM an idea of how much damage will occur in their county so that they can begin planning recovery operations.

Much of the weather information for tropical events that is currently available to EM can be hard to find and understand, and some information, such as surge forecasts, are released too late to be useful in many pre-storm operational decisions such as evacuations. To examine these issues and assess EM needs for surge and wave information, an evaluation of the North Carolina-Coastal Emergency Risks Assessment (NC-CERA)tool was conducted. This visualization tool was developed at the Department of Homeland Security Coastal Hazards Center of Excellence at the University of North Carolina at Chapel Hill.

NC-CERA visualizes the output of the ADvanced CIRCulation surge model (ADCIRC) and Simulating Waves Nearshore (SWAN) model, which provide a single deterministic surge and wave forecast for five days based off of the National Hurricane Center Consensus Hurricane Advisory. The models and visualization are intended to provide additional surge and wave guidance to EM during coastal storm events threatening the North Carolina coast. The goal of the evaluation is to improve the NC-CERA tool so that it better meets the needs of the North Carolina coastal EM community and will be an additional resource that they use operationally during a tropical event.

To carry out this evaluation, a four step iterative process is used that was established in the Weather for Emergency Management Decision Support Project (WxEM). Conducted by the University of North Carolina and East Carolina University in collaboration with the NWS Office of Science and Technology, WxEM established the method to learn about EM processes, decisions, and weather information needs in order to improve decision support. To evaluate NC-CERA, county EM directors from each coastal county as well as several river surge counties (15 counties in all) participated in the various steps of evaluation, starting with the establishment of a baseline understanding of their decisions and processes during tropical events in general, and the surge and waves aspects specifically. The second step is to learn about EM current practices, including where they get surge and wave information, and identify gaps in what EM need and what they currently use. The third step is to make improvements to the NC-CERA tool based on information collected in steps one and two and during an initial demonstration of the tool. The final step, validation, is to assess if and how EMs used the tool during operations or an exercise.

This paper will review the methods used to gather information from EM about the NC-CERA tool and surge and wave information in general, preliminary results of the evaluation, and the next steps in the tool's development to improve the visualization of surge and waves for the EM community.