FLASH FLOOD WARNING SYSTEM IN MOUNTAINOUS AREAS USING X-BAND WEATHER RADARS SOME PRELIMINARY RESULTS OBTAINED IN THE FRAMEWORK OF THE "RHYTMME" PROJECT

In most cases, natural hazards encountered in mountainous areas are largely dependent on precipitations: flash floods, debris flows, landslides, rock falls, snow avalanches. However, the knowledge of rainfall quantities still remains a tricky issue: the available rain-gauges are in a limited number and most often located in the valleys, and the radar rainfall estimates have to deal with a lot of problems due to the relief and the difficulty to distinguish the different types of hydrometeors (snow, hail, rain). In this context, the “RHYTMME” project (Westrelin and al., 2010) deals with two main issues: