Climate-induced glacier retreat and permafrost degradation are significantly affecting hazards and risks in high mountain regions. Mobile water bodies, both in existing and newly forming lakes, are increasingly located close to steep slopes. These slopes often show reduced stability as a result of glacial de-buttressing and weakening permafrost strength. This combination of processes can lead to cascading failure events, where one hazardous process triggers a sequence of further destructive processes with far-reaching consequences. Recent catastrophic events in the Indian Himalaya, such as Chamoli (2021) and South Lhonak (2023), with severe damage to hydropower infrastructure, clearly illustrate this emerging challenge.

Such climate-induced changes in hazard conditions have not always been adequately considered in existing long-term concessions for hydropower infrastructure in cold, ice-affected mountains. There is therefore a clear need to reassess safety aspects, not only for planned projects but also for existing infrastructure.

For example, in the catchment of the Gepatsch reservoir in the Austrian Kaunertal, the Alpine Permafrost Index Map provides information on the current distribution of permafrost and glaciers. Similar datasets exist worldwide, including projections of future glacier retreat and potential lake formation. Indicators also exist for failure-susceptible slopes. Complex model chains are available to estimating the reach and impacts of large slope failures that may trigger tsunamis in lakes, leading to flood waves and subsequent debris flows.

This body of scientific knowledge provides an essential basis for assessing hazard potential and developing long-term safety concepts and disaster risk reduction strategies.