WSL Institute for Snow and Avalanche Research SLF

Understanding the physics of an avalanche

The Swiss Alps are known for their beauty and great skiing, but with the mountains also comes great danger. Globally, over 150 people die in avalanches each year, with an average of 19 in the Swiss Alps alone.

The WSL Institute for Snow and Avalanche Research SLF (SLF) based in Davos, Switzerland, is dedicated to research on snow, atmosphere, natural hazards, permafrost and mountain ecosystems. It operates one of the world’s biggest experimental sites at Vallee de la Sionne (VdlS), Switzerland where it measures full-scale avalanches.

Its research has led to a good understanding of how avalanches form, enabling reliable bulletins of potential risks for people and infrastructure in the area. However, it is still not possible to predict in detail exactly why, when and where an avalanche will be triggered.

SLF conducts laboratory and field research into how weak layers are formed in the snowpack, how fractures form and propagate, and how the snowpack eventually begins to slide and become an avalanche.

“We measure avalanches to protect people and understand the effects of climate change,” says Betty Sovilla, SLF researcher. “We are trying to understand the physics of the process of avalanches. This helps us to develop models that are used to map avalanches and help design protective structures for people and infrastructure.”

To collect data vital to this research, SLF uses Simcenter™ SCADAS™ RS hardware, part of the Siemens Xcelerator business platform of software, hardware and services.

Tough conditions require tough tools

Gathering data in a mountainous region is no easy task. “We have different structures along the mountain like wedges and a big pylon with different sensors attached that measure the impact force of the avalanche,” says Jens Kaufmann, SLF electrical engineer. “It also has temperature sensors at different heights and high-speed cameras with spotlights that measure particles moving within the powder cloud.”

This hardware is installed in the mountains in areas that are impossible to reach as they are covered under meters of snow. “We can’t access the mountain during avalanche season, and our headquarters is hours away in Davos,” says Kaufmann. “Simcenter SCADAS RS gives us the vital ability to remotely monitor data with its unique connectivity capabilities.”

Siemens partner BSIM Engineering helped SLF find the right solution that would collect all the necessary data in the most efficient, safe and reliable way. BSIM Engineering also worked with SLF to get the equipment installed and were on-hand throughout for technical support.

SLF chose Simcenter SCADAS RS for data acquisition as it is designed to withstand high loads up to 10 root mean square acceleration in G-force units (gRMS) and 100g shock. It also has ingress protection (IP)66/67 against water and dust and can be used in temperatures ranging from -40 Celsius (°C) and -40 Fahrenheit (°F) up to +65 °C and +150 °F. The distributed setup of the Simcenter SCADAS RS units covers the entire mountain surface and are located hundred meters from each other.

The flexible mounting capabilities of the units also made the solution well suited for the mountain environment. They can be stacked on top of each other with a built-in slide and latch mechanism and then fixed to the pylon with strap belts at the exact required position.

“Simcenter SCADAS RS is the perfect tool for this kind of research as it is a rugged system designed for harsh environments,” says Ricarda Nugk, BSIM Engineering sales and business development executive. “This isn’t the norm for testing equipment so it was the only solution that could do everything that SLF needs. It can withstand subzero temperatures, water and vibrations, which are all present during an avalanche.”

Verifying physical forces with numerical models

The objective for SLF is to achieve excellent accuracy in predicting avalanche trajectories and precisely measuring the forces they exert on essential infrastructure. With natural avalanches occurring as frequently as once or twice a week, rapid data collection is vital to capture all the important data within the two minutes that a typical avalanche lasts. This crucial data is immediately exported and coupled with simulation tools for in-depth analysis, continuously improving SLF’s understanding of avalanche behavior and enhancing safety protocols.

Data collected at the VdlS test site are exceptionally diverse and provide a unique foundation for verifying and validating the different components of SLF’s numerical avalanche models. “The avalanche dynamics measurements acquired with Simcenter SCADAS RS inside the instrumented pylon and the radar-based flow dynamics system allow us to reconstruct the temporal evolution of flow velocity with high precision,” says Johan Gaume, chair of Alpine Mass Movements, which investigates the mechanics and rheology of granular flows and gravitational mass movements occurring in mountain environments and contributes to mitigation and land-use planning solutions. “These observations offer essential constraints for understanding the mechanical behavior of dense and powder snow avalanches and for developing rheological models that reproduce these processes realistically.”

In parallel, the distributed impact-pressure sensors positioned on obstacles along the avalanche path deliver high-resolution records of dynamic loading, which is indispensable for assessing and refining the pressure relationships predicted by numerical simulations. Such relationships guide land-use planning and the design of protective structures in avalanche-prone areas.

“More broadly, as our models become increasingly detailed and incorporate ever more physical processes, the availability of high-quality real-world data becomes even more critical,” says Gaume. “Datasets such as those from VdlS not only contribute to validate our models but also reveal their limitations, highlight missing physics, and directly inform future developments. Using Simcenter SCADAS RS makes this possible.”