3D Blatten model aims to improve Switzerland’s landslide-risk planning

A 5.4-metre replica of Blatten is giving Swiss researchers a new way to test how mountain slopes move. The WSL Institute for Snow and Avalanche Research SLF has recreated the Valais landscape at a scale of 1:577, then installed the model in a former military bunker near Davos. Researchers are using it to examine how landslides and other mass movements travel across complex terrain.

The work matters because computer simulations guide decisions about where people can live, where roads and utilities can be built, and when authorities may need to issue warnings. A more reliable understanding of flow behaviour could help cantonal and municipal authorities refine those assessments for settlements and infrastructure.

The Blatten model follows intense efforts to understand the forces shaping Alpine communities. Mountain slopes can carry water, rock, soil and debris through channels and into populated valleys. The SLF experiments offer a controlled setting where scientists can repeat those movements, alter conditions and measure the results. The project does not predict a specific future event in Blatten. It strengthens the evidence available when officials assess hazards in places with similar terrain.

The physical model contains 56 individually printed parts and took around 100 days to produce. Its dimensions, 5.4 metres by 4.5 metres, allow the researchers to reproduce the shape of the landscape on a scale large enough for controlled flow experiments. The SLF describes the model as a long-term investment in research.

That scale gives the team room to observe how material spreads, accelerates and settles as it crosses slopes and channels. Scientists can compare what happens in different sections of the terrain and use the measurements to test the assumptions built into digital hazard models. The physical setup also makes the movement visible in ways that can be difficult to capture through computer modelling alone.

The installation sits near Davos, far from the Valais valley it represents. Its value lies in the precision of the reconstruction and the ability to run repeatable tests. Researchers can examine the same landscape under controlled conditions, then use the resulting data to improve simulations that authorities may rely on when evaluating roads, buildings and other infrastructure exposed to natural hazards.

Water, sand and clay become a controlled stand-in for a mountain mass movement. During each experiment, the SLF channels the mixture across the model and records how it behaves. Cameras track the movement, lasers map changes and sensors capture measurements including flow speed, discharge levels and the deposits left behind.

Johan Gaume, who heads the SLF’s Alpine Landslides research group, said the team is focusing on the role of terrain curvature in flow dynamics. Curved terrain can redirect moving material, influence its speed and change where debris accumulates. Those details matter when officials estimate which parts of a valley could be exposed.

The experiments can also show where digital models need adjustment. Researchers compare the observed movement with computer predictions, identify differences and improve the formulas used in future assessments. The tests cannot reproduce every factor in a real Alpine event, including changing weather and geological conditions. They can, however, isolate the effect of terrain shape and provide measured evidence for a key part of hazard analysis.

The practical test for the Blatten project will come in planning offices and emergency rooms across Switzerland. Cantonal and municipal authorities use hazard assessments when they consider development, protect infrastructure and prepare responses for communities in exposed valleys. Better computer models could give them a clearer picture of how a mass movement might travel through local terrain.

The results may support early-warning work, but the source material does not assign the model a role in issuing a specific alert system. Its stated purpose is to improve the reliability of the simulations authorities will use in future risk assessments. That distinction matters: research data can strengthen decisions, while responsibility for land-use rules and emergency action remains with the relevant public authorities.

The project also adds to wider Swiss research into changing mountain hazards. The SLF and other experts are studying landslides, glacier retreat, permafrost and the forces behind major Alpine collapses. For residents of Blatten and other mountain communities, that research can inform long-term choices about where to build, what to protect and how to prepare as pressure on steep terrain grows.