Abstract:The rainfall forecast in mountainous region generally has high uncertainty,and the measurement and real-time transfer of actual rainfall data is difficult and expensive.Based on information technologies,including smartphones and cloud computing,the framework of an interactive flood warning system was proposed and tested for ungauged mountainous regions according to the mass prediction and prevention principle.Firstly,geographic coordinates and rainfall estimate inputs from local residents were collected via smartphone terminal.Then the parallel hydrological model on the cloud server was automatically executed to simulate the rainfall-runoff process. Finally,according to the allowed flood discharge at different locations,warning levels were derived from runoff simulation results and pushed to the rainfall information provider and potential flood sufferers via smartphones.Because of the high efficiency of data collection and hydrological simulation,residents can receive warning information before the flood arrives,and save time to escape.The application of this system would essentially improve the technical level of mass prediction and prevention.