A hydrologic–hydrodynamic model of the Yi River basins in Uruguay has been developed as a support tool to the Emergency Coordination Centre of Durazno city. The purpose was to improve the existing decision support system and the emergency planning by providing information on gauge height and its permanence in time, and the risk of flooded areas. Four past flood events of high return period were used for calibration and validation with accurate results. The input data to the operational model in real time are hourly observed rainfall and gauge height, as well as rainfall forecasts by several international sources. The use of predictions fromnumerical weather forecasts allows for the generation of pre-alert scenarios with larger lead time. These scenarios can warn the emergency coordinators, and thus are of great value to premanage a probable emergency. Operation of a meteorological weather alert issued by the National Meteorological Board is discussed.