Snowfall in the Hindu Kush Himalayas is declining at an alarming pace, raising serious concerns for river systems, ecosystems and water security across South and Southeast Asia. Scientists warn that increasing snow droughts in the region could have devastating ripple effects for downstream river basins that support nearly two billion people across eight countries.
From the Indus to the Mekong, shrinking snowpacks are shortening snow-covered seasons and weakening the natural water storage that mountain snow provides, threatening agriculture, hydropower generation and drinking water supplies far beyond the mountains.
Vanishing snow witnessed on the ground
In the high-altitude region of Spiti in Himachal Pradesh, researchers documenting snow conditions encountered striking evidence of change. Local yak herders described winters that are now warmer and shorter than they remember, with snowfall arriving late and disappearing early. Some even reported changes in animal breeding cycles, a signal of shifting seasonal patterns.
Field measurements in parts of Kullu district showed snow depths of just 40 to 50 centimetres in January, far below the several metres of snow the region once received. The lower layers of snow were already wet, indicating early snowmelt that would normally begin months later.
What snow droughts really mean
A snow drought refers to an unusually low amount of snowpack during a particular season, distinguishing it from traditional rainfall-related droughts. Scientists classify snow droughts into two types. Dry snow droughts occur when winter precipitation is below normal, leading to insufficient snowfall. Warm snow droughts happen when precipitation is near normal but temperatures are high enough for rain to replace snow or cause early melting.
Recent research published in Scientific Reports shows that both types of snow droughts are increasing across the Hindu Kush Himalayas, driven primarily by rising temperatures.
River basins under growing stress
The study identifies major river basins such as the Indus, Ganga, Brahmaputra, Mekong and Amu Darya as increasingly vulnerable. Snow cover periods are becoming shorter, especially at elevations between 3,000 and 6,000 metres, where warming has a stronger impact.
Snow cover days across the Hindu Kush Himalayas have declined by about five days per decade. Climate projections suggest that future snowfall in some basins could drop by 30% to 70%, severely reducing the water available during dry months when snowmelt is crucial.
Hotspots of snow drought across the Himalayas
Researchers found frequent snow drought events in the North-West, Amu Darya, Indus, Ganga, Mekong and Salween basins. Regions in Afghanistan emerged as major hotspots, while parts of Ladakh, Jammu and Kashmir and Himachal Pradesh also showed clear signs of snow drought stress.
In China, areas within the Salween and Mekong basins, including parts of Qinghai and the Tibet Autonomous Region, experienced similar trends. Moderate to severe snow droughts were recorded in several years, closely linked to declining snow cover persistence.
Why mid-elevation zones are most vulnerable
Elevations between 3,000 and 6,000 metres face the greatest risk due to what scientists call elevation-dependent warming. Small temperature increases at these heights can cause snowfall to turn into rain, reducing snow accumulation and accelerating melt.
As a result, these zones are losing their ability to store water naturally, increasing the frequency and intensity of snow drought events.
Impacts on water, power and livelihoods
Reduced snowmelt in summer lowers river flows, affecting reservoirs, irrigation systems and drinking water supplies. Hydropower projects that rely on predictable snow-fed flows face declining generation and operational uncertainty.
In winter, more rainfall instead of snow increases the risk of floods and rain-on-snow events, complicating water management. Tourism and winter sports also suffer as snow-reliant activities become increasingly unreliable.
Lessons from global snow drought trends
Globally, snow droughts are projected to become three to four times more common by the end of the century. Warm snow droughts are expected to dominate, accounting for nearly two-thirds of future events.
Similar patterns have already been observed in the western United States and the European Alps, where reduced snowpack has disrupted water management and hydropower production, offering a glimpse of what may lie ahead for the Himalayas.
The urgent need for monitoring and adaptation
Experts stress that snow droughts in the Himalayas remain under-monitored due to limited ground observations and coarse-resolution data. Improved monitoring, data sharing and regional cooperation are essential to managing future risks.
Proposed adaptation strategies include investing in water storage infrastructure, improving irrigation efficiency, restoring mountain ecosystems and adopting flexible reservoir management. Policymakers are urged to act swiftly, as the changing snow regime threatens to reshape water security across one of the world’s most critical mountain regions.