Flash droughts are a recently recognized type of extreme event distinguished by sudden onset and rapid intensification of drought conditions with severe impacts. They unfold on subseasonal-to-seasonal timescales (weeks to months), presenting a new challenge for the surge of interest in improving subseasonal-to-seasonal prediction. Here we discuss existing prediction capability for flash droughts and what is needed to establish their predictability. We place them in the context of synoptic to centennial phenomena, consider how they could be incorporated into early warning systems and risk management, and propose two definitions. The growing awareness that flash droughts involve particular processes and severe impacts, and probably a climate change dimension, makes them a compelling frontier for research, monitoring and prediction.

旱灾是最近公认的一种极端事件，其特征是干旱条件的突然发作和迅速加剧，并带来严重影响。它们以季节到季节的时间尺度（数周到数月）展开，这对提高季节到季节的预测兴趣引起了新的挑战。在这里，我们讨论了山洪干旱的现有预测能力以及建立其可预测性所需的条件。我们将其置于百年现象的背景下，考虑如何将其纳入预警系统和风险管理中，并提出两个定义。人们日益认识到，旱灾涉及特定的过程和严重的影响，甚至可能涉及气候变化，这使它们成为研究，监测和预测的引人注目的领域。