An integrated approach for GLOF hazard, vulnerability and risk assessment in the Karakoram Mountain Range of northern Pakistan

Climate change and rising temperatures are accelerating the rate of deglaciation in the Hindu Kush Karakoram Himalaya (HKH) ranges, leading to the formation of new glacial lakes and the expansion of existing ones. These lakes are often vulnerable to failure, posing a significant threat to downstream communities and infrastructure. Therefore, a comprehensive assessment of Glacier-Lake Outburst Flood (GLOF) hazards and risk assessment is crucial to evaluate flood runout characteristics and identify settlements and infrastructure that are exposed and vulnerable to floods, aiding in the development and implementation of risk reduction strategies. This study aims to simulate a GLOF event induced by the Shisper glacier lake in northern Pakistan, using the HEC-RAS, and to assess its impact on settlements, infrastructure, and agricultural land. For the hydrometeorological analysis of the GLOF event, topographic data from unmanned aerial vehicles (UAVs), stream profiles, discharge data, Manning's roughness coefficient (n), and land use/land cover (LULC) were analyzed using HEC-RAS and geographic information system (GIS). During the GLOF event on May 7, 2022, a maximum water depth of 6.3 m and a maximum velocity of 9.5 m/s were recorded. Based on the runout characteristics of this event, vulnerability and risk assessments have been calculated. The physical, social, and environmental vulnerabilities of the at-risk elements were evaluated using the analytical hierarchy process (AHP) and integrated with the hazard data to develop a risk map. The study identified the areas, infrastructure and settlements susceptible to GLOF hazard to support the development and implementation of targeted and evidence-based mitigation and adaptation strategies.