- 1Climate Change Impacts and Risks in the Anthropocene (C-CIA), Institute for Environmental Sciences, University of Geneva, Geneva, Switzerland (yan.zhong@etu.unige.ch)
- 2Department of Geography, University of Zurich, Zurich, Switzerland
- 3School of Earth and Environmental Sciences, Lanzhou University, Lanzhou, China
- 4Independent journalist/water policy researcher, Uttarakhand, India
- 5Planetary Science Institute, Tucson, Arizona, USA
- 6Department of Geography and Regional Science, University of Graz, Graz, Austria
- 7Midui Glacier-Guangxie Lake Disaster Field Science Observation and Research Station of Tibet Autonomous Region, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
- 8Department of Earth Sciences, University of Geneva, Geneva, Switzerland
- 9Department F.-A. Forel for Environmental and Aquatic Sciences, University of Geneva, Geneva, Switzerland
Hydropower projects across the High Mountain Asia (HMA) region have attracted substantial investment in recent decades, with institutions such as the World Bank and the Asian Development Bank funding projects worth hundreds of billions of dollars. However, hydropower development in this region faces severe challenges from natural hazards, particularly rock and/or ice avalanches (RIAs) and their cascading processes. RIAs can produce between 10 million and 100 million cubic meters of sediment—equivalent to 2% to 20% of the Yangtze River’s annual sediment transport. These mass flows are sudden, powerful, and come with little warning, posing major and long-lasting threats to hydropower installations (HPIs), local communities, and river systems. A notable example is the 2021 Chamoli disaster in India, which destroyed two hydropower projects, killed more than 200 people, and impacted downstream areas over 50 kilometers away.
To mitigate economic losses, optimize investments, and enhance hydropower planning in HMA, this study evaluates the potential risk of RIAs to HPIs across the region. A comprehensive dataset of HPIs, including dams, intakes, and powerhouses, was compiled for this purpose. Potential RIA hazards were assessed by analyzing all steep slopes within glacial and periglacial domains, with downstream trajectories to HPIs calculated. This assessment utilized an iterative GIS-based model, designed to automatically assess the risk to each HPI and enable large-scale automated applications.
Our results show that there are currently 1,819 HPIs in the HMA, around 53% (968) of which are threatened by RIAs and their cascading processes. With ongoing hydropower development, the number is planned to increase to 2,611 in the future, with those at risk rising to 57% (1,413). High- and very high-risk HPIs are predominantly concentrated along the Ganges River basin, particularly in Nepal, where a 3-fold increase in future risk is anticipated, including within critical transboundary hotspots. Compared to GLOFs, potential RIAs starting zones are more numerous and unpredictable, while in combination, RIA’s can initiate devastating cascading process chains from glacial lakes, amplifying risk to HPIs. To ensure sustainable development, future hydropower planning in the HMA region must account for the threat of RIAs, emphasizing strategic site selection, appropriate HPI types, and enhanced risk management strategies.
How to cite: Zhong, Y., Allen, S., Bu, X., Upadhyay, K., Kargel, J., Steiner, J., Zheng, G., and Stoffel, M.: Cascading rock and ice avalanches are a widespread threat to High Mountain Asia hydropower installations, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15938, https://doi.org/10.5194/egusphere-egu25-15938, 2025.
