Operational snowcover simulations with avalanche dynamics calculations coupling to assess avalanche danger in high altitude mining operations

The Codelco Andina copper mine is operating in high alpine terrain where avalanches pose a threat to the operations and the infrastructure. A dedicated avalanche warning service is responsible for opening and closing the heavily used access road. To support their decision making process, a system is developed in which numerical snowpack modelling is coupled to avalanche dynamics simulations to assess avalanche risks. The primary system output is an assessment of snow cover stability as well as avalanche size and runout. Based on measurements from automatic weather stations, the temporal evolution of the snowpack is simulated using the SNOWPACK model. This model is run within the spatially explicit Alpine3D tool, taking into account the radiation budget in complex terrain. The SNOWPACK model provides snowpack stability estimates and, based on the weak layer depth, potential fracture depths and snowpack properties of the slab. For example, for wet snow avalanches, which is the major threat in the mine, the simulations indicate if water is accumulating at layer boundaries inside the snowpack. The model accumulation depth defines the potential fracture height. This information is displayed on maps, but is also directly used to provide the initial conditions for the avalanche dynamics model RAMMS for predetermined avalanche paths. The properties of the entrained snow, which we show is also an important factor to determine avalanche runout, are also provided by the Alpine3D simulations. The system in which real-time snow cover simulations are combined with avalanche dynamics simulations is a novel approach to provide avalanche forecasters with a new source of objective information to aid the avalanche risk assessment