Abstract: Flash drought is a rapidly intensifying process of water shortage characterized by unexpected occurrence, rapid development, severe intensity, and extreme destructiveness. The rate of drought onset is a crucial feature distinguishing traditional drought and flash drought. Flash drought, as a “new normal” type of drought, is increasing in frequency and severity under global warming. Clarification of the impacts of flash drought on agricultural production and quantification its impacts on crops are helpful for fully understanding the impacts of drought disaster on crops, which is of great significance for stable and high grain yields in China and even in the world. In this review, we summarize research progress on the characteristics, definition, drivers, and main identification methods of flash drought in the past decade. We elaborate the methods of assessing the impacts of flash drought on crop growth, the sensitivity of crops to flash drought, the physiological mechanism by which flash drought affects crop growth and development, and the impacts of flash drought on crop yields. Challenges remain in the study of the effect mechanism and assessment of crop loss attributable to flash drought. For example, discrimination of traditional drought and flash drought events remains unresolved, the mechanism by which flash drought affects crop growth and yield is unclear, the ability to simulate and evaluate the effects of flash drought on crops is inadequate. Future research should focus on the following aspects: establishing methods for identification of flash drought suitable for different regions, different crops, and different growth stages; clarifying the differences in the effect mechanism between traditional drought and flash drought on crops; quantitatively simulating the responses of crop growth to flash drought, and clarifying the effects of flash drought on crop growth and yields.

Key words: flash drought, extreme event, crop, identification method, effect evaluation.