Hindu Kush Himalaya Snow Persistence Hits 23-Year Low, Signaling Water Security Risks

The Hindu Kush Himalaya (HKH) region, often referred to as the "Third Pole" due to its extensive ice and snow reserves, is facing a critical water security challenge, underscored by a sharp decline in seasonal snow persistence during the 2024-2025 winter season. This period marked the third consecutive year of below-normal snow accumulation, resulting in a 23-year record low for snow persistence. Data from the 2025 Snow Update by the International Centre for Integrated Mountain Development (ICIMOD) indicated that snow persistence was 23.6 percent below the 20-year average spanning 2003 to 2023.

Snow persistence, which measures the duration snow remains on the ground between November and March, serves as a crucial indicator for future water availability, as snowmelt contributes nearly 23 percent of the annual river flow for the region's major river systems. This substantial reduction in the natural water reservoir directly threatens the water security of approximately two billion people sustained by the 12 major river basins originating in the HKH, which traverse nine nations including India, Nepal, and Pakistan. The deficit was observed across all 12 basins; the Mekong and Salween basins recorded the most significant decreases, falling 51.9 percent and 48.3 percent below normal, respectively.

For densely populated areas, the Ganga basin experienced its lowest persistence in 23 years at 24.1 percent below normal, while the Brahmaputra basin registered a 27.9 percent deficit. This diminished meltwater input places stress on agriculture, hydropower generation, and essential drinking water supplies, particularly as demand peaks during the early summer months. Compounding surface water issues, nearly half of the base flow sources for the Indian Himalayan Region's springs are reportedly drying up or becoming seasonal, impacting groundwater outlets relied upon by an estimated 200 million people across India's mountain systems.

The decline in base flow and the drying of springs are linked to erratic weather patterns, including extended dry periods, and extensive land-use changes such as infrastructure development and deforestation, which reduce the soil's capacity for groundwater recharge. Immediate human impact is evident, such as the relocation of communities in Nepal's Samdong village following the drying of a glacier-fed stream. ICIMOD Director General Pema Gyamtsho emphasized the necessity of a paradigm shift in water governance, stating that recurrent snow anomalies are already a consequence of existing carbon emissions, demanding immediate regional cooperation and science-led adaptation strategies to manage intensifying water insecurity.