Risk of water shortages builds-up as Hindu Kush Himalaya faces 23-year-record-low snow persistence in the third consecutive year of below-normal seasonal snow

According to the latest Snow Update Report, the Hindu Kush Himalaya (HKH) region experienced its third consecutive below-normal snow year in 2025, with snow persistence – the fraction of time snow is on the ground after snowfall–hitting a vicennial record low of – 23.6%. This is worrying news for water security of nearly two billion people across 12 major river basins that originate high in the HKH.

Launching the 2025 Snow Update report, Pema Gyamtsho, ICIMOD’s Director General, emphasised the need for proactive policy actions in building long-term resilience to exacerbating snow anomalies: “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.”

On average, 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. Despite such basin-wise differences in the dependency on seasonal snowmelt, continued deficit of seasonal meltwater, in general, means lesser river runoffs and early-summer water stress, especially for downstream communities, already reeling under premature and intensifying heat spells across the region.

According to Sher Muhammad, Remote Sensing Specialist at ICIMOD and the lead expert for Snow report 2025: “We are observing such deficit situations occurring in continuous succession. This is an alarming trend. While our findings give broad picture across the region, each must act based on the specific conditions of their river basins, particularly where seasonal snow melt is the major water source.

While the level of deficit in snow persistence in the western river basins, this year, has been less compared to the last year, it provides no respite from the existing water stress in these areas. Seasonal snowmelt is critical for water supply in these basins. So, persisting below-normal snowfall and reduced melt rate will only worsen water availability.

On the other hand, the eastern river basins, which experienced near normal snow persistence last year, face deficits up to 50% below normal. Although seasonal snow contributes less to total meltwater here, around 15% drop in persistence of seasonal snow could still impact downstream communities, especially in the mountains and Tibetan Plateau, where annual snow conditions are generally erratic.”

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.

Monitoring a 23-year timeseries (from 2003 to 2025) of basin-scale snow persistence during the snow season between November and March, the report shows recurrent seasonal deficits, coupled with severe yearly fluctuations. Moreso, over the last five years.

Yellow River Basin: From a high of +98.2% in 2008 to a low of -54.1% in 2023, the basin continues facing deficits, albeit at -18.6% in 2025. Such sustained deficits strain agriculture, hydropower, and water availability. 

Yangtze Basin: 2025 saw a -26.3% snow persistence—the sixth lowest in 23 years. Steadily declining snowpack jeopardises hydropower efficiency of the Three Gorges dam. 

Mekong Basin: 2025 saw a record low snow persistence of -51.9%, down from a peak of +80.3% in 2019. Severe fluctuations risk disrupting hydropower and agriculture.

Salween Basin: Here also, snow persistence showed steep fluctuations from a highest of +41.9% in 2020 to the lowest of -48.3% in 2025.

Brahmaputra Basin: Snow persistence peaked in 2019 at +27.7% but steadily dropped to -27.9% in 2025. This continued decline poses risks to hydropower generation and agriculture, especially in early summer, calling for integrated drought risk planning. 

Tibetan Plateau: Snow persistence in the Plateau plummeted from a +92.4% in 2022 to -29.1% in 2025. These extreme changes highlight the plateau’s climate sensitivity. 

Tarim Basin: Snow persistence peaked at +28.7% in 2006 and dropped to -26.9% in 2024, while 2025 records -4%. This basin has seen six consecutive years of below-normal snow, raising long-term concerns for reliable water availability.

Ganges Basin: Basin recorded highest snow persistence at +30.2% in 2015, but it dropped to the 23-year lowest of -24.1% in 2025. This would likely reduce flows in early summer .

Indus Basin: From a high of +19.5% in 2020, the basin experienced a steep drop in snow persistence to -24.5% in 2024, its vicennial lowest. In 2025, the basin recorded snow persistence anomaly at -16%. This sustained deficit threatens early summer water supply for nearly 300 million people, calling for urgent water management strategies. 

Helmand Basin: After a record low of -45.0% in 2018, and a peak at +49.2% in 2020, 2025 saw a relatively moderate deficit at -15.2%. Persistent deficits, however, aggravate Afghanistan’s water stress and socioeconomic vulnerabilities. 

Amu Darya Basin: Snow persistence peaked at +40.4% in 2008 but dropped to -31.9% in 2024. In 2025, it was recorded at -18.8%, ranking the fourth lowest in the last 23 years. This consistent deficit in seasonal snow will threaten downstream water availability.

Experts of the report emphasis immediate need for basin-level targeted actions toward adaptive water resource management for mitigating forthcoming impacts of water shortages on agriculture, hydropower generation, and other vital ecosystem services.

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 key action areas recommended in the report.

Download the report: Link

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Neraz Tuladhar (Raz), Media Officer
Email: media@icimod.org