The first session of ISSW2018 deals with the topic of avalanche dynamics, which examines the flow behavior of avalanches in the broadest sense. Current research is multi-pronged - some scientists study large avalanches experimentally, others try to simulate and measure effects in the laboratory, and others develop and use computer models. Nowadays, computer models are becoming increasingly important and so it is not surprising *who* got the very first talk at the conference:

## What do avalanche dynamics have to do with Disney's animation studios?

For some time now, a win-win situation has been inspiring snow science. During a stay in Los Angeles, the young professor and professional snowboarder Johan Gaume developed a snow model together with Disney that not only looks good but also works exceptionally well (O1.1). If you want to know what it looks like, you can visit the current movie "The Ice Queen 2". If you want to follow the scientific scope of the model, we recommend Johan's Twitter channel or the website of the SLAB (snow and avalanche simulation laboratory) at EPFL in Lausanne.

The fascinating thing about the model is that it simulates the properties of snow and all applications such as fracture mechanics and flow dynamics arise from this. Technically, the model is based on the "Material Points Method" (short explanatory video). Instead of being based on a rigid computational grid, "Material Points" (quasi individual snow grains or granules/snowballs) are defined, which carry properties such as mass, momentum and deformation. This enables simulation over several orders of magnitude - i.e. from the weak layer in the centimeter range to the flow of the avalanche in the hundred-meter range. Furthermore, it is precisely this simulation method that is suitable for modeling transitions from solid mechanics to flow dynamics: The stationary snowpack behaves like a deformable solid, but the avalanche behaves more like a granular fluid.