Influences of the snow cover on thermal and mechanical processes in steep permafrost Rockwalls

This project investigates the influences of the snow cover on thermal processes in steep Alpine permafrost rock walls. The latter typically remain at a temperature below 0°C for at least two consecutive years, irrespective of the presence of water or ice. Water and ice at the rock surface and within fractures can however potentially have serious implications on the thermal, hydraulic and mechanical properties of steep rock. Degrading permafrost in ice-bearing rock walls can for example be a hazard due to rockfall activity or slow rock deformation, which can affect the stability of mountain infrastructure. Snow probably has a key role determining both rock temperatures and ice/water contents of rock walls and thus influences mechanical processes in steep terrain. To obtain a better understanding of these processes and their triggers, the temporal and spatial evolution of the snow cover and its physical characteristics in rock walls are investigated using in-situ methods such as snow pits and remote-sensing techniques such as terrestrial laser scanning and time-lapse photography. Various meteorological instruments are tested to measure the surface heat fluxes in complex terrain with patchy snow distribution. Near-surface rock temperatures and deep borehole thermal regimes are monitored in parallel. Our project partners at the University of Bonn in Germany investigate the mechanical impacts of the snow cover and snow melt water infiltration into rock walls using geoelectrical methods to determine ice/water content, geophones to monitor fracturing activity and crack-meters to assess fracture deformation. In a final step, using the assimilated data, future snow scenarios are used to model and gauge the potential sensitivity of permafrost affected rock walls. This will help to identify the range of possible responses of permafrost rock walls to the effects of changing climate.

• Publications
  • Haberkorn Anna, Hoelzle Martin, Phillips Marcia, Kenner Robert (2015), Snow as a driving factor of rock surface temperatures in steep rough rock walls, in COLD REGIONS SCIENCE AND TECHNOLOGY, 118, 64-75.
  • Haberkorn Anna, Phillips Marcia, Kenner Robert, Rhyner Hansueli, Bavay Mathias, Galos Stephan P., Hoelzle Martin (2015), Thermal regime of rock and its relation to snow cover in steep Alpine rock walls: Gemsstock, central Swiss Alps, in Geografiska Annaler, 1-19.
  • Haberkorn Anna, Phillips Marcia, Kenner Robert, Schmid Marc-Olivier, Influences of snow cover on thermal processes in steep Alpine permafrost rock walls.