By Dhurjati Mukherjee
The nature and scale of disasters are becoming increasingly hazardous, affecting millions of people across the world. This is starkly evident in the very recent glacial flood disaster in Nepal. The disaster was reportedly triggered by the bursting of a glacial lake formed following a landslide. Satellite imagery reviewed by The New York Times indicated that the lake had breached, unleashing a massive flood and causing widespread devastation. Scientists at the International Centre for Integrated Mountain Development (ICIMOD) estimate that a large volume of ice and rock debris resulted in a powerful surge of water, sediment and boulders downstream. Such cascading behaviour has been witnessed before in the Himalayas, reviving comparisons with the 2021 Chamoli tragedy in Uttarakhand when a massive rock and ice avalanche triggered a deluge, killing 200 people and destroying two hydropower projects. According to geoscientists, a rock-ice avalanche is dangerous because it may set in motion a chain reaction. Experts pointed out that warm temperatures are adding to the instability of high mountain environments.
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As per available statistics, there are 2070 glacial lakes in Nepal, 21 of which are classified as high risk, as per a 2020 report by the ICIMOD. There are many more surrounding lakes in the Himalayan areas of China and India. There were altogether 135 GLOF (glacial lake outburst flood) events in the Karakoram region from 1900 to 2000, and the present century has already witnessed around 85. As the region is full of glaciers – around 22,800 sq. km in the Himalayas and the area is warming faster than the planet, the region is susceptible to more such floods. Higher temperatures and rainfall are accelerating this change and that is the reason why such events occur from June to August. Scientists see a lot of glaciers melting in the coming years and, by some estimates, 65% of the ice mass region could disappear by 2100.
In such a situation, roughly 1 million people who live within 10 km of a glacial lake are susceptible to the growing risk of disasters and it would be necessary to relocate them away from narrow river valleys and go easy on infrastructure projects in mountainous areas. As regards India, it needs to be stated that this country witnesses the highest number of fatalities from GLOF, similar to the one witnessed in Nepal. It would be pertinent to mention that a paper titled ‘Glacial Outburst Flood Risks, Response Strategies & Adaptation Gaps in the Hindu Kush Himalayan Region’, which covers data from 1995 to 2025, found that China witnessed 199 GLOFs, followed by Pakistan (152) and India (62) and Nepal (5). The paper rightly pointed out that climate factors meaning acceleration of warming, especially since the start of this century, led to the increasing frequency of such avalanches.
Experts warn that a far greater disaster could strike the region if adequate safety measures are not strictly enforced and vulnerable populations are not relocated to safer areas, preferably at least 5–10 km away from glaciers and glacial lakes. There is an urgent need for an inter-governmental mechanism involving India, Bhutan and Nepal, and perhaps China, to formulate a coordinated long-term strategy for monitoring glaciers, assessing risks and preventing or mitigating GLOFs. Given that glaciers and glacial lakes do not recognise national boundaries, regional cooperation, real-time data sharing and an effective early-warning system are imperative.
