To address the issues associated with flash floods, especially the lack of capacity to develop effective flash flood warnings, the Flash Flood Guidance System (FFGS) was designed and developed for interactive use by meteorological and hydrological forecasters throughout the world. FFGS is necessary to provide operational forecasters and disaster management agencies with real-time informational guidance products pertaining to the threat of small-scale flash flooding. FFGS is a robust system designed to provide the products needed to support the development of flash flood warnings from rainfall events using remote-sensed precipitation (that is, radar and satellite-based rainfall estimates) and hydrological models. To assess the threat of a local flash flood, FFGS allows product adjustments based on the forecaster’s experience with local conditions; incorporation of information, such as Numerical Weather Prediction outputs; and any last minute local observations, including non-traditional rain gauge data or local observer reports.