Abstract ID: 3.13383 | Accepted as Poster | Poster | TBA | TBA

Glacial Lake Outburst Floods (GLOFs) pose a significant and growing risk in high mountainous regions. The rapidly changing climate is accelerating glacier retreats, which expands existing lakes and creates new ones, leading to an increased frequency of GLOFs. This risk is further intensified by the rising likelihood of GLOF triggers such as temperature increases, extreme rainfall, or ice collapse, resulting in severe downstream impacts. In the Hindukush Himalaya (HKH), particularly in Afghanistan region, studies and understanding on these triggering processes and downstream consequences remain very rare. We studied two catastrophic GLOF events in Peshghor, Panjshir Valley of Afghanistan: The Kunj-Peshghor GLOF (July 12, 2018) and the Bam-Tanab GLOF (July 4, 2021). Both events initiated by debris-ice dammed glacial lakes, caused massive socio-economic impacts, including loss of people, destruction of houses, irrigation canals, micro-hydropower and infrastructures. In this ongoing research we are planning to evaluate climatic drivers (pre-event) and downstream impacts (post-event), with a focus on hydrological changes in the river as well as flood inundation and propagations under different dam breaching scenarios, using remote sensing data, field-based assessments and the BASEMENT model. Our preliminary results show that the 2018 GLOF, occurred 43 days after lake formation, from a rapidly expanding lake on the surface of a debris-covered glacier, driven by rising temperatures and fast ice and snow-melting. The mean discharge has increased from 75 m³/sec to 160 m³/sec, mean water levels rise from 1.75 m to 2.50 m, and water turbidity peaked to over 1000 MTU in the main Panjshir river. And the sediment deposit dammed the Panjshir main river up to 1.7 km from the confluence. Similarly, the 2021 Bam-Tanab GLOF, occurred within 33 days after lake formation, triggered by a combination of temperature rise and a short rainfall event. Both outbursts were released through a subglacial channel, eroding ice and debris. These events indicate the increasing risk from rapidly growing lakes resulted by a climatic factor in the region. This study emphasizes the need for early warning systems and community resilience measures to GLOF hazards, with a particular emphasis on the role of sediment transport and water quality in flood impacts.