Snow shed design is based in practice on simple hydrodynamic equations. The dynamic forces exerted by an avalanche are a function of flow velocities, flow height and slope deviation angle. Between 2002 and 2006, scale experiments using granular material on a laboratory chute as well as large chute experiments with snow on the Weissfluhjoch (Davos) were used to determine the relevant dynamic parameters of avalanches flowing over an inclined plane with a deviation. The performed experiments result in an improved approach to calculate the dynamic forces due to a deviation and in more detailed data on the coefficient of friction depending on the snow type. The new findings were implemented in the revision of design guidelines for snow sheds. The guidelines describe the design concept, typical load cases and formulas to calculate the avalanche actions. Finally practical results from an application of the guidelines are presented.