Dehradun: Seasonal snow persistence -- the duration for which snow remains on the ground without immediately melting -- across the Hindu Kush Himalaya (HKH) has fallen to 27.8% below normal in 2026, the lowest in over two decades, raising concerns about water security for nearly two billion people, according to the latest annual snow update by the International Centre for Integrated Mountain Development (ICIMOD).
This is the fourth consecutive year of below-normal snow levels, indicating a sustained decline in snow reserves across the region. Experts warned that reduced snow accumulation during winter could affect river flows in the coming months. Snowmelt remains a key source of water, particularly in early summer when rainfall is limited, and a weaker snowpack could lead to lower runoff and increase the risk of water stress.
Basin-Wise Declines and Regional Variability
The impact is significant for major basins such as the Indus, Amu Darya and Helmand, which depend heavily on snowmelt. Overall, 10 of the 12 major river basins in the HKH region have recorded below-normal snow persistence, with several witnessing sharp declines.
The steepest declines were recorded in the Mekong basin (down 59.5%) and the Tibetan Plateau (down 47.4%). Other basins also saw significant drops, including the Salween (41.8%), Yellow River (35.9%), Amu Darya (31.8%) and Tarim (27%). Key snow-fed basins such as the Helmand and Indus also reported declines, with snow levels falling by around 18% in each.
However, some regions recorded above-normal snow levels. The Irrawaddy basin saw an increase of 21.8%, while the Ganga basin recorded a rise of 16.3%, indicating regional variability in snow patterns.
Implications for Water Resources
“Meltwater from snow contributes around 23% to the total river runoff in the HKH region on average, with the share of snowmelt increasing from east to west,” the ICIMOD report said. The continued deficit could affect agriculture, hydropower generation and drinking water supply in downstream regions. “The sustained decline in snow persistence is a critical signal of changing cryospheric conditions under a warming climate,” it said.
Scientists linked the trend to rising temperatures and changing precipitation patterns associated with climate change. With snow reserves shrinking and demand for water increasing, experts said the region could face greater vulnerability in the coming years.
ICIMOD has called for urgent action, including improved water management, better seasonal forecasting and regional cooperation among countries dependent on Himalayan river systems.
