Analysis of the Historic Oklahoma Panhandle Flash Flood Event of 18-19 June 2024 through the Use of Aerial Imagery and the Flash Flood Severity Index

A number of detailed flash flood surveys were conducted across the southern Plain during the spring of 2024 in an effort to better understand the coverage and impacts of significant flash flood events. These multifaceted surveys included the combination of ground surveys, uncrewed aircraft systems (UAS), high-resolution satellite tasking, data collection from broadcast and social media, reports from local officials, results from online societal surveys, and analysis of traffic mobility data. The use of UAS and high-resolution satellite imagery provided a unique perspective on the flash flooding impacts and how it correlates with and supplements what was found with on-site ground surveys and other data collections. Each identified impact had its severity categorized using an updated version of the Flash Flood Severity Index (FFSI) that is currently undergoing field testing in the National Weather Service (NWS). This allows for the spatial quantification of the impacts and severity of each event and its comparison to rainfall and hydrologic products, vulnerable locations, and topographic features.

The overnight period into the early morning hours of 18-19 June 2024 saw an extreme precipitation event across portions of the Oklahoma panhandle. Areas in Texas County and portions of neighboring Beaver County received 6-10 inches of rain during this event, which translates to some areas receiving half the average annual rainfall in less than 12 hours. This record rainfall resulted in historic flash flooding and large-scale areal flooding across the region. Dozens of structures were flooded with several water rescues conducted in the region, numerous roads were washed out or damaged, and many areas remained underwater for days. On-site surveys were conducted by personnel from the University of Oklahoma Cooperative Institute for Severe and High-Impact Weather Research and Operations (CIWRO), the National Severe Storms Laboratory (NSSL), and the NWS forecast office in Amarillo, TX. This presentation will focus on the aerial-based imagery collected from the event, the analysis and corroboration of the impacts from the aerial imaging with ground surveys, and the ability to quantify the severity of the impacts using FFSI. Moreover, the mapping of these impacts to topographic features and vulnerable locations can provide insight into how future research can incorporate this information to improve forecasting and warnings of flash flooding as well as new efforts towards more human-centered, impact-based applications.