Flash Drought Timing and Winter Wheat Productivity in the Southern Great Plains of the United States

Flash droughts are highly impactful, subseasonal to seasonal events that pose a severe risk to agricultural production. Within the United States, these rapidly intensifying droughts have the potential to cause tens of billions of dollars of crop loss and long-lasting impacts to the overall U.S. economy. This study examined flash drought events across a vital agricultural region of winter wheat production in the United States spanning the 40-yr period from 1981 to 2020. The southern Great Plains was selected given 1) the agriculturally dense winter wheat cultivation and 2) the high frequency of flash drought occurrence in this region. The standardized evaporative stress ratio (SESR) was used to identify and analyze flash drought events’ spatial coverage, the rapidity of onset, and spread across the region. These events are defined as simultaneous flash droughts (SFDs) within this study and provide critical information regarding recent changes in flash droughts and the potential impacts to agricultural producers. The results demonstrated that flash drought events which develop and intensify between July and October have significant negative impacts on winter wheat productivity and overall reduced yields. Conversely, SFDs that occur toward the end of the life cycle have minimal impacts and may result in above-average winter wheat yields.