Abstract: Local rainstorms is the most important factor that induces flash floods in mountainous areas. Effective non-engineering means to reduce flash flood losses includes strengthening rainfall monitoring in small watersheds, analyzing and calculating critical rainfall index values, and issuing effective warning information in time. Previous research on flash flood disasters mainly focuses on short-term near warning and prediction, paying little attention to monitoring technology for heavy rainfall typed flash floods. The spatial and temporal scale of flash flood outbreaks is specific, and traditional monitoring network cannot meet the monitoring requirements posed by high intensity and short duration of flash floods. Therefore, it is challenging to build a cross-scale flash flood monitoring system. This paper reviews the research progress of rainfall monitoring technology, including rain gauge, weather radar, satellite remote sensing, microwave link rain measurement, and rainfall fusion technology. Although flash flood monitoring technology is developing continuously, single monitoring transmission means and information sources cannot meet the requirements of flash flood monitoring in complex mountainous environments. In this paper, a three-dimensional monitoring technology system for flash floods can provide real-time rainfall monitoring data and technical support for flash flood process simulation, flood risk assessment, warning, and forecast.

Key words: heavy rainfall and flash flood, monitoring technique, rain gauge, weather radar, satellite remote sensing, rainfall fusion