Estimation of powder snow avalanche impact pressures with OpenFOAM

Snow avalanches are usually released from a collapsing snow pack in steep alpine terrain. Their initial movement can be described as dense granular flow (density around 200 kg/m³). The dense core is often accompanied by a dilute ice-air suspension (density around 10 kg/m³). These powder snow avalanches (PSA) reach velocities up to 100 m/s and heights up to 200 m. They often exceed the runout of the dense core, leading to significant damage. There is little knowledge about the structure of PSA and their interaction with obstacles, such as defense structures, bridges and buildings. Measurements are severely constrained by the destructive power of PSA and their infrequent occurrence. To overcome these issues, we investigate PSA with numerical models. We use OpenFOAMs multiphase solver to simulate the interaction between PSA and obstacles. Results are used to derive recommendations for resilient building in vulnerable areas and the design of defense structures.

We gratefully acknowledge the financial support by the OEAW project "beyond dense flow avalanches". The computational results presented have been achieved (in part) using the HPC infrastructure LEO of the University of Innsbruck.