ALBERT

Beschreibung: This study explores the hazard of avalanches in high mountain Asia (HMA), an area that not only sustains livelihoods through water storage, but also holds potential for natural disasters. Although there is limited research on the complex relationship between climate and triggers of avalanches, this study reviews available literature to identify research gaps and proposes future directions for research and mitigation strategies. In this study, available literature was reviewed covering the period from the late 20th century to June 2022 to identify research and societal gaps and propose future directions of research and mitigation strategies. Beyond scientific literature, technical reports, newspapers, social media and other local sources were consulted to compile a comprehensive, open access and version-controlled database of avalanche events and their associated impacts. Over 681 avalanches with more than 3131 human fatalities were identified in eight countries of the region. Afghanistan has the highest recorded avalanche fatalities (1057) followed by India (952) and Nepal (508). Additionally, 564 people lost their lives while climbing peaks above 4500 m a.s.l., one third of which were hired staff. Although fatalities are significant, and local long-term impacts of avalanches may be considerable, so far, limited holistic adaptation or mitigation measures exist in the region. Considering the high impact avalanches have in the region we suggest to further develop adaptation measures including hazard zonation maps based on datasets of historic events and modelling efforts. More research studies should also be attempted to understand trends and drivers of avalanches in the region.

Beschreibung: Glacial Lake Outburst Floods (GLOFs) are a major hazard in high mountain areas, and can significantly impact transportation infrastructure, human settlements, water supplies, agricultural land, and important cultural and religious locations. Dynamic flow models are widely used for hazard assessment, preparedness planning and to support Early Warning Systems for other destructive sediment flows including flash floods and debris flows, and here we present results of their application and calibration for GLOFs. We use the LaharFlow model (www.laharflow.bristol.ac.uk), a dynamic sediment flow model for hazard assessment, which solves conservation equations for mass and momentum under the shallow layer approximation, to compute the flow dynamic properties. LaharFlow includes parameterizations for erosion and deposition, and the variation in flow solids concentration, friction and landscape change that result, and is freely-available as a webtool. We applied the model to recent case studies that represent a range of GLOF sizes: at Ghulkin (Pakistan, 2022), Shisper (Pakistan, 2020) and Lemthang Tsho (Bhutan, 2015), and also to potential future impacts on Paro (Bhutan). Source conditions were constrained using estimates of lake volumes and idealised hydrographs corresponding to an instantaneous moraine wall failure and slow drainage. The modelling shows good agreement for observed flow depths, speeds, erosion patterns and arrival times using parameters calibrated for other large debris flow settings. For the Paro example, we show how dynamic models can be used to identify locations for, and calibrate, early warning systems, and to assess potential impacts of GLOFs on communities living in high mountain environments.