Progress of research on the methods for the early warning of mountain flash flood disasters

Accurate and timely warning is vital for the prevention and control of mountain flash flooding disasters in small- and medium-sized basins, but it is also the most challenging issue. Focusing on the key issue of mountain flash flooding warning, a state-of-art review is done from three aspects, including spatial difference of characteristics of mountain flash flooding disasters in China, techniques and methods for flash flood warning, and development of probabilistic warning methods for mountain flash flooding control. It is indicated that the temporal and spatial differences of characteristics of mountain flash flooding disasters are noticeable across China, thus it is necessary to develop suitable early warning system in specific areas based on their special needs. The indicator of critical rainfall is an important basis of mountain flash flooding warning in China, however, a fixed critical rainfall estimated by proper statistical methods or hydrological model, as commonly done in practice, cannot meet the needs enough in China, as it does not perform well sometimes and cannot handle the uncertainty of warning results. Alternatively, probabilistic warning of mountain flash flooding disasters, which can quantitatively evaluate the uncertainty of warning results, has its theoretical advantages and potential wide application ranges, and thus could be a more adaptive approach. In order to develop the probabilistic warning methods of mountain flash flooding disasters, the following key issues are suggested to be concerned and solved: (1) mine detailed information from different sources of rainstorm and flash floods data, based on which to develop effective methods for the probabilistic warning of mountain flash flooding disasters; (2) concern the nonstationary issue encountered commonly in hydrology study, and explore its influences on the estimation of proper critical rainfall and also the accuracy of probabilistic warning results; and (3) establish an integrated flash flood warning system by considering both the occurrence probability of critical rainfall and its resulting probability of mountain flash flooding disasters, serving for the practical prevention and control of mountain flash flooding disasters.

Recommended citation: Ren, Z., Sang, Y. F., Yang, M., Wang, Y., & Shang, L. (2023). Progress of research on the methods for the early warning of mountain flash flood disasters (in Chinese). Progress in Geography, 42(1):185-196. DOI:10.18306/dlkxjz.2023.01.015.
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