It has been hard not to despair while watching the ruinous floods swallow parts of Nepal, and harder, still knowing that the agony compounds each passing day for dozens of Indian families whose members remain unaccounted for. Social media is awash with desperate pleas, photos and details of the young and old, men and women, from Mumbai to Kolkata, posted by families searching for traces of life. The disaster unfolded when a melting glacier slammed into the valley below, unleashing a deadly cascade of rock and ice down the Bhote Kashi River, which flows from Tibet into Nepal.
Among the 275 Indians missing at the time of writing are workers of a hydropower project and people undertaking the Hindu pilgrimage to Mount Kailash in Tibet. Another 128 people of Indian origin, including a large group of Sadhguru’s Isha Foundation spiritual group, are also missing; 149 Indian people have been rescued as of Monday. For Gauri Joshi, whose five relatives remained unaccounted for over the weekend, the last few days have been a blur of calling their numbers in vain, watching news of rescue operations and trying to reach Indian officials – over and over again.
What she has pieced together so far is that her relatives, part of a pilgrim tour group from Maharashtra, cleared immigration at the Gyirong border between Nepal and Tibet and boarded buses shortly before the flood waters destroyed the crossing. But maybe a miracle will happen,” Joshi said. The tragedy has reignited the question of how vulnerable the Himalayas are to climate change, and what its implications are for India.
To understand the risks of glacier collapse and thawing permafrost leading to sudden floods and debris flows, I spoke to Dr Ashim Sattar, a professor at Indian Institute of Technology Bhubaneswar and an expert on glacial lake outburst floods. The conversation has been edited and condensed. What are the climate- or glacier-related risks emerging across the Himalayas?
In a layperson’s terms, the cryosphere is where water exists in solid form, for example a glacier. When it melts, it forms glacial lakes. If they have an outburst, they can cause damage downstream.
Another cryospheric component is glacier ice. This is what we’ve seen in Nepal, where a glacier detachment happened. The frontal part of the glacier detached from the main glacier and eventually led to a debris flow.
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