Driving through the Appalachians, I often wonder how my American neighbours would react to the wondrous might that is the Hindu Kush Himalaya (HKH). English poet William Wordsworth discovered the sublime looking at the Alps, a puny mountain range compared to the HKH. And this might is not just about height. The HKH region is one of the world’s most important mountain water systems, acting as Asia’s water tower. This colloquial phrase in the hydrological parlance underscores the region’s critical role in sustaining the continent’s freshwater supply. Its glaciers, seasonal snowpack, groundwater-fed springs, and monsoon precipitation sustain the Indus, Ganges, and Brahmaputra River systems and support hundreds of millions of people in China, India, Pakistan, Nepal, Bhutan, and Bangladesh. The HKH contains more than 63,700 glaciers and approximately 5,736 cubic kilometres of estimated ice reserves, making it one of Asia’s most important natural water-storage systems.

Now for the worrying part. Recent assessments indicate that glacier wastage has accelerated substantially since 2000, increasing concerns about both future water availability and cryosphere-related hazards. From a hydrogeological perspective, Himalayan rivers are components of interconnected surface-water and groundwater systems. Snowmelt, glacier melt, rainfall, groundwater discharge, and monsoon runoff contribute to streamflow at different times of the year. The climate crisis is altering this balance. While accelerated glacier melting can initially increase runoff and cause floods, continued retreat ultimately reduces the volume of stored ice available to sustain downstream flows, causing droughts. At the same time, glacier retreat can produce and enlarge glacial lakes, increasing the potential for glacial lake outburst floods (GLOFs). A 2026 review documented more than 388 GLOF events across the Himalaya-Karakoram region and identified ice avalanches and extreme precipitation among important triggers. The October 2023 South Lhonak GLOF in Sikkim and........

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