Abstract ID: 3.11013 | Accepted as Talk | Talk/Oral | TBA | TBA

For high alpine routes, glacier retreat and rockfall have a major impact on accessibility and safety. While glacier retreat in the Alps is well documented and mapped, there is much less information on the influence of climate change on rockfall processes. In this study, we analysed where rockfalls occur in relation to permafrost degradation and glacier retreat in the Stubai and Ötztal Alps in the Eastern Alps. Using area-wide digital terrain models from 2006 and 2017 based on laserscanning data, we made an inventory of rockfalls above the tree line. We identified a total of 1989 rockfalls with volumes ranging from 200 m³ to 200,000 m³. Notably, 76% of the rockfalls occurred in areas with a mean annual ground temperature (MAGT) below 0°C, which represents only 22% of the potential rockfall area. In addition, 40% of the rockfalls occurred in areas that have deglaciated since 1969, representing only 4.7% of the potential rockfall area. The presence of permafrost and glaciers depends on altitude and slope exposure. This dependence on slope exposure and altitude is therefore reflected in the spatial distribution of rockfalls. Rock faces in the northern sectors and above 3000 m are particularly prone to rockfall. Although only 22% of rock faces are above 3000 m, 75% of all rockfalls occurred at this altitude. The rockfall inventory shows where rockfall occurs but not when. Correlating the timing of rockfall with meteorological events and anomalies (heat waves, temperature drops and fluctuations, frost and thaw cycles, sudden snowmelt combined with heavy rainfall, etc.) will allow us to study rockfall triggers and the timing of rockfall. The mountaineering community can contribute with observations and reports of high alpine rockfall. This is a first step towards predicting which weather conditions are more likely to trigger rockfall and will lead to an increase in rockfall.