The work carried out in this thesis deals with the case study case reported by Dr. Giovanni Cavagnino, who was assigned the study of snow avalanches on the stretch of provincial road SP82 that connects the municipalities of Piode and Rassa (VC), in Val Sesia, and the design of risk mitigation works. As a part of this study, the numerical modelling of snow avalanches and the drafting of risk maps are two fundamental operations, which will be described in the following chapters. Local evidence shows that almost every time there is a snowfall and a subsequent rise in temperatures, small avalanches involve the road: these are events with an annual recurrence that cause closure for a short period of the road, the only way of communication between the towns.