In August 2005, the North of France's Nothern Alpine Region was hit by serious flooding. This study briefly describes what was forecast by EFAS for the Upper Danube in August 2005, and it illustrates the potential contribution of probabilistic forecasts to incresaing the forcast period lead time and anticipating flood vents. The case study is completed by a statistical analysis of the performance of the EFAS forecasts, conduced on the whole of the Danube basin over a period of three months during the Summer of 2005.