Simulation is a helpful go-to tool for assessing risk, but what if the event being simulated is an avalanche – a complex event with countless parameters and physical variables?
With input from Gaume and a team of mathematicians, the highly accurate digital simulation offers insight into the workings of an avalanche – information that will help to improve forecasting and hazard management in snow-covered, mountainous regions.
And did you know much of the simulation inspiration came from a Disney movie?
Gaume spoke with Tech Briefs spoke about how he and his collaborators at UCLA were able to digitally recreate a massive slide of snow.
Tech Briefs: Why is an avalanche so challenging to simulate?
Johan Gaume: An avalanche is very complicated to simulate because snow is an extremely complex material whose mechanical behavior is not fully understood yet. In addition, we focused on snow slab avalanches, which are not only the most destructive but also the most complex avalanches involving challenging crack propagation mechanisms. Finally, up to now, we lacked a unified numerical framework able to simulate both the initiation and the flow of the avalanche at the slope scale.
Tech Briefs: How does your simulation approach differ from traditional methods?
Gaume: Traditional methods focus either on the release or on the flow of the avalanche, independently. Here, we are able to simulate the whole avalanche process in a unified manner. In particular, we are able to evaluate – for the first time – the position and volume of the release zone, which is required in operational risk management procedures.
Furthermore, we were able to reproduce very well the so-called process of "anticrack" propagation in weak snowpack layers which is at the origin of snow slab avalanches. This process refers to the collapse of the very porous weak layer which is buried below the snow slab, similar to the collapse of a house of cards. (Learn more about the simulation method at EPFL.)
Tech Briefs: What inspired this work?
Gaume: This work was largely inspired by the snow model developed initially for the movie Frozen. When I first saw the movie, I was amazed by the realism of snow deformation and failure.
I thus contacted Prof. Joseph Teran, a mathematician at the University of California Los Angeles (UCLA) who was involved in the Frozen snow simulations. He was very motivated by the idea of extending the model to avalanches, and I submitted a proposal to get funding from the Swiss National Science Foundation, to go to LA and work with his team and colleagues: Dr. Ted Gast at UCLA and Prof. Chenfanfu Jiang at UPenn.
Tech Briefs: How was your science background helpful to this effort?
Gaume: My background is mostly in Solid and Fluid Mechanics, and I apply it to model snow and avalanches, but so far using rather simple approaches.
It was really the combination between the skills and talent of the UCLA and UPenn mathematicians in numerical modeling and my knowledge in snow and avalanche mechanics which led to the success of this collaboration. We were not only able to make avalanches "look good," but the model was also validated using real-world data from the WSL Institute for Snow and Avalanche Research SLF.
Tech Briefs: Can this type of simulation be used in other applications?
Gaume: Beyond avalanche forecasting and risk management, our simulations could be used in Computer-Generated Imagery (CGI) for movies or video games for example. In general, the powder-cloud is quite well simulated in movies of avalanches (or a volcano's pyroclastic flow), but the initiation of the avalanche could be significantly improved using our approach. Finally, I think this work has interesting applications in other domains such as landslides, debris-flows, rockfall, and more generally, simulation of granular materials.
Tech Briefs: What’s most exciting to you about this research?
Gaume: Personally, the most exciting part was the collaboration and working with extremely talented mathematicians. I was impressed by how fast they could turn a new physical process into mathematical equations. I learned a lot at UCLA! For the work itself, being able to simulate an entire avalanche in 3D on a realistic terrain is definitely the most exciting.
Tech Briefs: What’s next?
Gaume: Now we would like to simulate avalanches based on real topography and snow cover properties in order to validate it with real-scale measurements of avalanches available in Switzerland. We also want to use and further develop this method to simulate sea ice and glacier calving.
Gaume and team’s research was published this month in Nature Communications.