Ganga basin records lowest snow persistence in 23 years: Report
The snow persistence in the Ganga basin this year has been 24.1% below normal — the lowest in the past 23 years, vis-à-vis 30.2% above normal (the highest) in 2015 — which could lead to reduced flows in early summer, the International Centre for Integrated Mountain Development (ICIMOD) has said.
Snow cover persistence anomaly during November 2024-March 2025 in the Ganga basin.
These reports provide year-wise analysis of seasonal (November-March) snow persistence.
Snow persistence over the Hindu Kush Himalayan (HKH) region has plummeted to a 23-year record low, registering a staggering 23.6% below the long-term average. This unprecedented level of reduced snow cover, which measures the fraction of time snow remains on the ground after snowfall, underscores a significant and growing threat to water security of nearly 2 billion people who are dependent on the HKH’s river systems, the ICIMOD said, adding that the alarming statistic is compounded by the fact that 2025 marks the third consecutive year of below-normal seasonal snow across the region.
“The cumulative impact of these persistent deficits is likely to result in substantially reduced river runoffs and increased potential for early-summer water stress, particularly affecting vulnerable downstream communities already grappling with intensifying heat waves,” the report said.
The consistently declining seasonal snow persistence and increasing snowmelt anomaly across the river basins in HKH, there is pressing need for immediate basin-level targeted actions, the ICIMOD has recommended.
Investing in adaptive infrastructure like seasonal storage systems and enhancing efficient use of meltwater, developing national preparedness and response plans for negative snow anomaly and drought conditions, integrating snow anomaly information into national water strategies for hydropower, agriculture, and allied sectors, and disseminating snow anomaly statistics to strengthen evidence-based decision making and sectoral coordination, are some of the recommended action points. At the same time, the HKH countries need to embrace a paradigmatic shift toward science-based, forward-looking policies and renewed regional cooperation to tackle the regional snow crisis and the challenges it creates for long-term food, water and energy resilience.
“Carbon emissions have already locked in an irreversible course of recurrent snow anomalies in the HKH. To tackle this regional snow crisis and the challenges it creates for long-term food, water and energy resilience, we urgently need to embrace a paradigm shift toward science-based, forward-looking policies and foster renewed regional cooperation for transboundary water management and emissions mitigation,” ICIMOD director general Pema Gyamtsho said in a statement.
On average, the seasonal snowmelt contributes about a fourth of the total annual runoff of these rivers, with the share gradually rising from the rivers in the east to those in the west of the region.
The report reveals the most alarming declines in snow persistence in the Mekong (-51.9%) and Salween (-48.3%) basins, followed by the Tibetan Plateau (-29.1%), the Brahmaputra (-27.9%), Yangtze (-26.3%), and the Ganges (-24.1%) basins.
