Debris flow susceptibility in a touristic alpine area: the case study of the Bardonecchia town (Upper Susa Valley, NW Italy)

Debris flows are among the most hazardous natural events in mountain areas due to their intensity, speed, and unpredictability. They can cause severe damage to buildings and infrastructure, often destroying homes, sweeping away bridges and vehicles, and burying roads and urban areas. In recent decades, changes in rainfall patterns and human expansion in the Italian Alps, many of which are tourist zones, have significantly increased debris flow risk. This calls for detailed vulnerability assessments and effective mitigation strategies. The case presented highlights the challenges faced in a high-risk, economically and tourist-relevant area. The aim of this study is to assess debris flow susceptibility in relation to a set of natural and human-induced factors, including landscape transformations, land use patterns, geo-morphological conditions, and the characteristics of past geo-hydrological events. Debris flow triggering susceptibility was analyzed using integrated techniques, ranging from historical-cartographic documentation to remote sensing methods.