FLASH FLOODING IN TENNESSEE: SPATIOTEMPORAL TRENDS AND HOT SPOTS (1996-2022)

Historical flash flood events in Tennessee counties from 1996 to 2022 (2849 recorded events) were analyzed to identify spatiotemporal trends and hot spots. Flash flood events and damages (in US$) recorded in the National Oceanic Atmospheric Agency (NOAA) storm events database were evaluated using trend and emerging hot spot analysis at an annual time step. Trend analysis revealed an uptrend in flash flood events in west Tennessee (Shelby and Tipton counties) and down-trends in thirteen counties distributed across the state, at a 90% or greater confidence level. Shelby county (west TN) and multiple counties in middle Tennessee were identified as flash flood event hot spots. Uptrends in flash flood-induced property damages were identified in middle Tennessee (four counties), and east Tennessee (two counties). Down trends were identified in two counties in west Tennessee. A consecutive hot spot for flash-flood-related damages was identified in west (Benton) and middle Tennessee (Houston and Humphreys counties). These results indicate that, while trends in flash flood events by county is mixed, with both increases and decreases, property damages caused by these floods are increasing, especially in middle Tennessee. This study is an important step forward in understanding spatiotemporal trends in flash flooding and flash flooding damages, and will be useful in hazard mitigation planning in Tennessee at both state and county levels.