ISRO Satellite Study Finds 676 Himalayan Glacier Lakes Have Grown Sharply Since 1984

Recent devastating floods in Nepal have refocused attention on the risks posed by glacial lakes and unstable mountains across the Himalaya. A new satellite study by the Indian Space Research Organisation (ISRO) has found that, of 2,431 glacial lakes larger than 10 hectares studied using satellite data going back to 1984, 676 have grown significantly in size.

Of these 676 growing lakes, 601 have more than doubled in size. A total of 130 of the 676 lie within India, spread across the Indus (65 lakes), Ganga (7 lakes) and Brahmaputra (58 lakes) river basins. Glacial lakes form when retreating glaciers and melting ice leave meltwater pooled behind them; some are held back by a natural dam of ice, rock or debris.

A separate 2026 satellite study covering all of High Mountain Asia recorded 31,698 glacial lakes in total, with their combined area growing 5.5% since 2016-17. The Eastern Himalaya saw the sharpest expansion, with lake area there growing by 14.1 square kilometers.

ISRO is continuously monitoring 2,024 glacial lakes during the monsoon season across the catchment areas of 26 hydropower projects run by NHPC (National Hydroelectric Power Corporation). Heavy rainfall, landslides and shifting mountain slopes can, at times, put extra pressure on the natural dams holding back these lakes.

According to ISRO's satellite data, more than 80,000 landslide events have been recorded across the Himalayan range so far.