The catastrophic flash flood that hit Nepal's Rasuwa district on 26 August is not merely a national tragedy. It is a warning to the whole of South Asia; a region whose climate, water, and food security are inseparably linked through the Hindu Kush, Himalaya mountain system and its transboundary rivers. Preliminary assessments suggest an ice-rock avalanche and landslide dammed the Lhende River near the Nepal–China border, forming a temporary debris-dammed lake; its sudden release sent a violent slurry of water, mud, rock, and sediment down the Bhote Koshi and Trishuli river systems. Hundreds are reported dead, nearly a thousand missing, and tens of thousands affected, with roads, bridges, settlements, and border facilities destroyed.

A shared mountain system under pressure

South Asia holds roughly one-quarter of humanity on less than 5% of the world's land, and more than 750 million South Asians have been affected by at least one climate-related disaster in the past two decades. The Himalayan cryosphere feeds 12 major river systems, sustaining about 240 million mountain residents and some 1.65 billion people downstream. What happens on Nepal's slopes therefore reaches irrigation, drinking water, food production, hydropower, and coastal cities across the region.

The exposure is measurable. An ICIMOD inventory counted 3,252 glaciers and 2,323 glacial lakes in Nepal; a more recent assessment mapped 2,070 glacial lakes in the Nepalese parts of the Koshi, Gandaki, and Karnali basins, with 21 classified as potentially dangerous. Across High Mountain Asia, around 15 million people are exposed to potential glacial lake outburst floods, making this the most........

© The Friday Times