This paper deals with the presentation of a flood warning system (FWS) developed for the specific characteristics of the Guadalhorce basin (SE of Spain). This is a poorly gauged basin and often affected by flash and plain floods. The system is oriented to provide distributed warnings based on rainfall accumulations and discharge forecasts, and fulfils the requirements of ungauged basins. The system is adapted to the use of distributed rainfall maps (such as radar rainfall estimates) and discharge forecasts are computed using a distributed rainfall-runoff model. Due to the lack of flow measurements, the model parameters calibrated on a small watershed have been transferred in most of the basin area. This work studies the performance of the system on two recent rainfall events which caused many inundations. First results show how the FWS performed well and was able to forecast the location and timing of flooding. It demonstrates that a simple model and a rough calibration could be enough to issue valuable warnings. Moreover, the European Flood Alert System (EFAS) forecasts have been used to provide a flood forecast several days in advance. With low resolution and long anticipation, EFAS appears as a good complement tool to improve flood forecasting and compensate for the short lead times of the GFWS.