In most cases, natural hazards encountered in mountainous regions are largely dependent on precipitations : flash floods, debris flows, landslides, rockfalls, snow avalanches and forest fires. To better understand the occurrence of these hazards and to prevent populations from their dangers, the knowledge of rainfall quantities at high temporal and spatial resolution is crucial. While the rain-gauge network is not dense enough to capture all the variability of precipitations, especially in rugged regions, radars can be very efficient. However, to install them in mountains as well as to retrieve real-time useful information remains a big challenge. To improve this radar information to elaborate warning services useful for the management of natural risks is another one. South-East of France is a mountainous region both very exposed to natural hazards and not well covered by radar measurements. In this context, the “RHYTMME” project (Westrelin & al, 2010 ; Mériaux & al, 2011) began in 2008 with the following main aims, both from research and operational objective: • to provide an accurate radar rainfall information in mountainous areas ; • to develop a real-time hazards warning system based on this information. The present paper gives an overview of the main achievements of the project in mid 2012.