This session is devoted to natural hazards and particularly gravitational mass flows that potentially interact with, and therefore endanger human assets. How far the natural hazard process propagates and how destructive it is are important questions for predicting such hazards and their damage potential. Observations, modelling and simulations are also used for forecasting and mitigating natural hazards. Contributions may include, but are not limited to, modelling & simulation approaches as well as observations & experiments on different scales. Particular emphasis is given to the interconnection and feedback between computational and experimental efforts in research, development and operational application.