Glacier dynamics, proglacial lake expansion, and GLOF risk assessment in the lato basin, Trans-Himalayan Ladakh

The accelerating retreat of glaciers and expansion of glacial lakes in the Trans-Himalayan region of Ladakh are intensifying the risk of Glacial Lake Outburst Floods (GLOFs), posing significant threats to vulnerable downstream communities. However, high-altitude basins like Lato remain poorly assessed in terms of integrated glacier–lake dynamics and hazard potential. In this study, we present a detailed, multi-parameter assessment of the Lato glacier–lake system over a 40-year period (1980–2020), combining remote sensing, empirical modeling, and hydrodynamic simulations. Our results show an ∼11.5% reduction in glacier area, a mean terminus retreat of ∼171 m at the rate of 4.2 m yr -1 , and a decline in total ice volume from 0.48 km 3 to 0.41 km 3 (1980–2020). Glacier surface velocities, derived using Glacier Image Velocimetry (GIV), ranged from 0.97 to 15.73 m yr -1 , with mean values between 7.63 and 8.03 m yr -1 . Ice thickness was estimated using GlabTop2 and ensemble modeling approaches, yielding average thicknesses of 76 m and 58 m, respectively. Geodetic mass balance calculations indicate a persistent negative trend, with an average loss of −0.33 m w.e. yr -1 since the early 2000s. The proglacial Lato lake expanded by ∼66%, reaching 0.088 km 2 in 2020. Lake depth and volume were estimated using multiple empirical models, with the most robust estimate placing the lake volume at 1.47 × 10 6 m 3 . GLOF susceptibility analysis using the Analytical Hierarchy Process (AHP) assigned a high-risk index of 0.82 to the lake. Two-dimensional hydrodynamic simulations using HEC-RAS under full and partial breach scenarios forecast peak discharges of 3726 m 3 s -1 and 2309 m 3 s -1 , respectively, with a potential impact zone extending ∼23 km downstream. This study not only identifies Lato lake as a high-risk GLOF site but also offers region-specific recommendations including glacier and lake monitoring, early warning systems, and the integration of GLOF risk into regional planning and disaster preparedness frameworks.