Within the European CADZIE project, physical experiments on small-scale models were conducted to study the effects of deflecting dams and mounds on powder snow avalanches. This interaction was simulated by physical modeling using unsteady gravity current flows. Three-dimensional experiments were carried out with different dam and mound characteristics. Front velocity and internal flow velocity profiles at different distances from the release point were compared with those obtained for the avalanche flow without a defense structure. With the densimetric Froude similitude, it was possible to quantify the effectiveness of different defense structures against powder snow avalanches with the data obtained in this experiment.