Abstract. Glacier lake outburst floods (GLOFs) have been intensely investigated in High Mountain Asia (HMA) in recent years and are the most well-known hazard associated with the cryosphere. As glaciers recede and surrounding slopes become increasingly unstable, such events are expected to increase, although current evidence for an increase in events is ambiguous. Many studies have investigated individual events and while several regional inventories exist, they either do not cover all types of GLOF or are geographically constrained. Further, downstream impacts are rarely discussed. Previous inventories have relied on academic sources and have not been combined with existing inventories of glaciers and lakes. In this study, we present the first comprehensive inventory of GLOFs in HMA, including details on the time of their occurrence, processes of lake formation and drainage involved as well as downstream impacts. We document 682 individual GLOFs that occurred between 1833 and 2022. Of these, 20 % were recurring events from just three ephemeral ice-dammed lakes. In combination, the documented events resulted in 6907 fatalities, with 6000 of these linked to a single GLOF, three times higher than a previous assessment for the region. The integration of previous inventories of glaciers and lakes within this database will inform future assessments of potential drivers of GLOFs, allowing more robust projections to be developed. The database and future, updated versions, are traceable, version controlled and can be directly incorporated into further analysis.

Abstract. The cryosphere in high mountain Asia (HMA) not only sustains livelihoods of people residing downstream through its capacity to store water but also holds potential for hazards. One of these hazards, avalanches, so far remains poorly studied as the complex relationship between climate and potential triggers is poorly understood due to lack of long-term observations, inaccessibility, severe weather conditions, and financial and logistic constraints. 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 staff employed as guides or porters. This makes it a less deadly hazard than in the less populated European Alps for example, but with a considerably larger number of people affected who did not voluntarily expose themselves to avalanche risk. 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. These measures generally rely on local and indigenous knowledge adapted with modern technologies. 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. This should however happen acknowledging the already existing knowledge in the region and in close coordination with communities and local government and civil society stakeholders. More research studies should also be attempted to understand trends and drivers of avalanches in the region.

Abstract. The cryosphere in high mountain Asia (HMA) not only sustains the livelihoods of people residing downstream through its capacity to store water but also holds the potential for hazards. One of these hazards, avalanches, so far remains inadequately studied, as the complex relationship between climate and potential triggers is poorly understood due to lack of long-term observations, inaccessibility, severe weather conditions, and financial and logistical constraints. In this study, the 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 staff employed as guides or porters. This makes it a less deadly hazard than in the less populated European Alps, for example, but with a considerably larger number of people affected who did not voluntarily expose themselves to avalanche risk. 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. These measures generally rely on local and indigenous knowledge adapted to modern technologies. 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. This should, however, happen acknowledging the already existing knowledge in the region and in close coordination with communities, local government and civil society stakeholders. More research studies should also be attempted to understand the trends and drivers of avalanches in the region.

No abstract