| 09 Dec 2025
How ice apron loss and permafrost degradation promote the Platteikogel rock slide: A thermo-mechanical reconstruction
Abstract. The Alpine cryosphere changes at unprecedented speed, affecting the thermal, hydrological, and mechanical state and behaviour of rock slopes. While numerous studies investigated singular drivers for progressive rock slope failures, the knowledge of hydro-thermo-mechanically coupled processes remains scarce. In this manuscript, we investigate the 2024 permafrost rock slide at Platteikogel with a volume of 50,000 m³ (3,395 m a.s.l., above Vernagtferner, Austria). We aim to assess how observed ice apron loss and related permafrost warming promote the release mechanism. We reconstructed multidecadal thermal evolution accounting for the thermal impact of ice apron loss. Based on field observations, we derived a conceptual model on how ice apron loss potentially affects rock slope destabilization. Integrating the outcome of the preceding steps, we performed a mechanical stability analysis assuming that the rock slide failed along ice-filled discontinuities. The mechanical model indicates that the rock slide can not be solely explained by a warming-driven decrease in shear strength of ice-filled discontinuities, suggesting that other failure processes superimpose or even dominate. The implemented system feedback related to ice apron loss suggests that hydrostatic pressure buildup due to water infiltration and rockfall-induced unloading thereby promoted the Platteikogel rock slide release. In summary, we demonstrate that ice apron loss not only leads to increased rockfall activity but also accelerates progressive rock slope failure, promoting the release of rock slides. In upcoming decades, ice aprons on steep rock slopes above 3000 m in the European Alps are expected to experience drastic area loss, exposing potential source zones for future rock slides.
Competing interests: At least one of the (co-)authors is a member of the editorial board of Earth Surface Dynamics.
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