Using Social Science Data for the Development of a Flash Flood Severity Index

This talk will address the successes and challenges of using societal data gathered through a NOAA-SBES grant, “Using Quick Response Surveys to Build a Public Perception and Response Database” to support the development of a new Flash Flood Severity Index (FFSI). FFSI categorizes the severity of flash flood events after they occur, using a scale with multiple impact categories ranging from very minor flooding to catastrophic flooding, allowing for a more detailed assessment of flood impacts compared to simple severity levels. The FFSI is currently being evaluated by several NWS Forecast Offices. The Quick Response Survey Project is creating a scientifically rigorous and operationally feasible survey system for NWS Weather Forecast Offices to collect data on human perception and response to tornados/thunderstorms, flash floods, and winter weather. By using consistent questions and methods, these surveys are intended to form the basis of a multi-year, cross-sectional database for NOAA. The surveys collect empirical data focusing on the period from individual hazard awareness through potential protective actions.

For the FFSI project, we collected detailed hydrometeorological, impacts, traffic mobility, and societal response data for several significant flash flood events that occurred in the Southern Plains in spring 2024. FSSI was evaluated through on-the-ground and aerial assessments to gather a complete picture of the coverage and severity of a specific flash flood event. Uncrewed aircraft systems (UAS) were deployed for the highest impact areas to test various camera methodologies, while on-demand satellite images were purchased to investigate their use for better identifying coverage areas. Each identified flash flood impact was associated with an FFSI value and correlated impact-based warning (IBW) threat tag. All impacts were mapped and gridded for comparison with NWS the Multi-Radar Multi-Sensor (MRMS) and Flooded Locations and Simulated Hydrographs (FLASH) systems. In addition, traffic mobility data was collected, and Quick Response Surveys of the public were conducted. The Quick Response Surveys address how different warning, environmental, social, and situational factors influence individual preparedness and response. Especially relevant for FFSI research are questions about the circumstances of the flooding that individuals experienced. The survey asks for the time and location of the floods, perceived water depths, whether individuals were in a building or car, whether they took protective actions (avoiding flooded roads, evacuating a building, etc.), and individual impacts of the flood. The societal survey data and traffic mobility data was mapped to explore correlations among public perceptions and experiences, impacts, FFSI/IBW designations, FLASH products, and traffic mobility data. This talk will present the results this research, focusing on the process of collecting and using the societal data, and how the societal data enhanced the research insights.