Flash Drought Risk and Agricultural Exposure in the Southeast United States

Abstract Flash droughts, defined by their rapid onset and potential for severe agricultural impacts, remain understudied in humid regions like the southeastern United States. This study presents a multi-indicator assessment of flash drought climatology from 2001 to 2023 across the Southeast using four metrics: the U.S. Drought Monitor (DM), evaporative stress index (ESI), soil moisture volatility index (SMVI), and the lawn and garden index (LGI). Flash droughts most commonly emerged during early summer and autumn, aligning with seasonal transitions in evapotranspiration and precipitation. SMVI identified the most events (mean = 24), while DM was the least sensitive (mean = 4). Regional hotspots, including central Georgia and eastern North Carolina, were consistently detected across indicators. To assess agricultural vulnerability, the study integrates crop-specific critical growth stages with flash drought detections using conditional probabilities. Corn showed the highest exposure, with 21% of years when a flash drought occurred during the crop’s most moisture critical stage, while DM-defined events aligned with critical stages in over 40% of cases. These results demonstrate that vulnerability is shaped not only by drought frequency but also by timing relative to crop development. The findings underscore the importance of multimetric approaches and regionally tailored frameworks to inform climate-resilient agricultural strategies in the Southeast. Significance Statement Flash droughts—rapid-onset droughts with severe impacts—occur nearly every year across the southeastern United States, yet their agricultural relevance is often overlooked. Using four widely used detection metrics, this study identifies a distinct flash drought climatology with peaks in early summer and fall. Timing and duration are key to understanding impacts. We show where and when flash droughts are most likely to harm crops in the Southeast by identifying how often they occur during key stages of crop growth—times when even short dry spells can seriously affect yields. By linking flash drought patterns to crop development, this work supports improved monitoring and informs adaptation strategies tailored to southeastern agriculture.