Climate-induced glacier vanishing and permafrost degradation affect hazards and risk in high mountains. Mobile water bodies in already existing but also newly forming lakes are close to steep slopes with reducing stability as a consequence of glacial de-buttressing and weakening permafrost strength. This more and more causes situations where destructive process cascades can take place and induce far-reaching consequences. The recent catastrophic events in the Indian Himalay at Chamoli (2021) and South Lhonak (2023) with heavy destruction of hydropower infrastructure strikingly document the challenge.

Such climate-induced change in hazard conditions has not commonly been considered in already existing, long-term concessions for hydropower infrastructure in cold, ice-affected mountains. A clear need therefore exists to re-examine the involved safety aspects, not only for planned future projects but also for already existing infrastructure.

For the catchment of the Gepatsch reservoir in the Austrian Kaunertal, the Alpine Permafrost Index Map illustrates the present-day occurrence of permafrost and glaciers. Similar information and additional quantitative data are available worldwide on future glacier retreat and anticipated lake formation. Indicators exist for failure-susceptible slopes with their potential runout distances. In addition, complex model chains are available for estimating reaches and consequences of large slope failures potentially triggering tsunamis in mobile water bodies with subsequent flood waves and debris flows. This scientific knowledge basis must be applied to assess hazard potentials as a basis for developing safety concepts and disaster risk reduction strategies.