An overview of flash drought: progress and challenges

Flash drought has received a worldwide concern in recent years due to increasing risk of concurrent drought and heat extremes, including those in Europe in 2003, North America in 2012, southern China in 2013, and southern Africa in 2016. While there is a controversy in the definition of flash drought, rapid onset and water deficit are regarded as two key characteristics. Rainfall deficit in the crop growing seasons is usually accompanied by heat waves, abnormally high temperature increases evapotranspiration and decreases soil moisture rapidly, and ultimately results in flash drought with a rapid onset, short duration but devastating impact. A number of studies have explored the drivers for the occurrences or long-term changes of flash droughts, compared them with conventional droughts, and investigated their ecological impacts. This presentation will review recent progress and discuss future challenges for flash drought, especially those related to mechanism understanding, attribution and impacts, as well as monitoring, prediction and projection.