Abrupt Agricultural Flash Drought: An Investigation of Rapid Drought Development Across Vital Agricultural Zones of the United States

Abstract

Flash droughts are highly impactful, subseasonal to seasonal events that pose a severe risk to agricultural production. The 2012 flash drought event in the United States is a prime example, as this event resulted in tens of billions of dollars of crop loss and caused longer-lasting effects to the overall US economy. This study examined impactful flash drought events across two agricultural regions of the central United States, spanning the 40-year period from 1981 to 2020. The two regions, the Southern Great Plains and Midwest, were selected given the agriculturally-dense areas in distinctively unique climate regions.

Using the standardized evaporative stress ratio (SESR), flash drought events were selected based on several factors, including the overall spatial coverage, rapid onset, and spread across the region. The events, defined as abrupt agricultural flash droughts (AAFDs), provide critical information regarding the timing of rapid drought transition across different areas of the United States and the implications they bring to agricultural producers. Initial results show that over the last 20 years, AAFDs have increased in frequency across critical regions of agricultural growth. Within the Southern Great Plains, essential findings within the timing of events illustrate how AAFDs, in conjunction with a winter La Niña pattern, led to a consistently below-average harvest of winter wheat the following growing season. Across the Midwest domain, results indicate a greater seasonality in AAFD events, with a majority of events transpiring during the late Spring and early Summer months.