Disposition of rock sediments and water in ice-rock mixtures

Rock-ice deposits can be divided into rock glaciers and chaotic ice-rock mixtures. Rock glaciers are stratified rock-ice features and can be several millennia old. Chaotic rock-ice deposits can be formed by e.g. catastrophic rock fall events. Recent events such as the Piz Cengalo rockfall have brought rock-ice deposits into focus. During this event large amounts of glacier ice were integrated into the rock avalanche deposit. Subsequent changes in the ice content, affecting the availability of sediments and influencing melt water flows, can provide material for ensuing debris- and mudflows, which can cause significant damage to infrastructure. Hence, there is a need to better understand the evolution of these ice-rock deposits.

This project employs numerical models to study the thermal regime of rock-ice deposits. On the one hand, physics-based models are able to better represent the actual processes and can help in improving understanding of them. However, they are computationally more expensive to run and need more detailed knowledge of the site to be modelled. On the other hand, empirical models can more easily be applied to larger, e.g. catchment, scales, which are needed to study the overall runoff and any potential changes thereof.

The main goals of this project are thus:

• modeling the thermal regime of selected rock glaciers under future climate scenarios and quantifying their importance in terms of long-term water reserves
• determining current/initial conditions for the modeling process by taking samples from recent chaotic rock-ice mixtures (e.g. at Val Strem, pictured);
• quantifying the importance of ice-rock deposits and rock glaciers in terms of material sources for secondary hazards such as debris- and mudflows.

This project is an integral part of WSL’s Climate Change Impacts on Alpine Mass Movements (CCAMM) initiative