Glacial Lake Inventory & GLOF Simulations

Due to climate change, the Northwesterner Gilgit Baltistan's, Ghizer district is highly susceptible to glacial lake outburst floods (GLOFs). Nearly 24 GLOFs have occurred in this area in the last ∼200 years, demonstrating the growing recurrent nature of these incidents. Taking this into account, the assessment of risks associated with GLOFs was investigated in this study. All regional glacial lakes were identified in the first phase, and changes between 2000 and 2023 were mapped using moderate-resolution satellite images (Landsat). To map built-up and agriculture areas, Landsat's lower resolution limited its use in such complex topography. Therefore Sentinel-2 data was used, and images from 2016 to 2023 were classified using a random forest (RF) classifier. A total of 617 glacial lakes covering ∼31.67 km2 of the area were mapped in 2023. Since 2000, ∼88 glacial lakes have appeared, showing an increasing trend in the number of lakes. In the second phase, categorization and susceptibility to GLOFs were assessed using multi-criteria decision analysis (MCDA). The grass GIS tool, r.avaflow, was used to generate GLOFs simulations based on friction, density, release area, travel time, and two travel time scenarios, i.e., 1800 and 3600 seconds, for four high-weighted glacial lakes. Results showed that the glacial lake near Darkut village, Yaseen Valley, poses a significant threat to downstream communities. In contrast, two other lakes in Gupis valley will have a moderate effect on the infrastructure and agriculture. The glacial lake of Punyal Valley poses no significant threat.