Even as Sikkim reels under the aftermath of a deadly glacial lake outburst flood (GLOF) in South Lhonak lake last October, another fast-expanding glacial lake in Uttarakhand Himalayas is becoming a cause for worry.
The Bhilangana Lake has grown to about 0.38 sq km area in the last 47 years, said Dr Kalachand Sain, Director of the Wadia Institute of Himalayan Geology (WIHG).
According to scientists, the rapid expansion of the glacial lake situated in the Bhagirathi catchment area is unsettling, as it can pose threat to people downstream, especially under the impact of rising temperatures.
“The lake is situated at a very high altitude and the slope downstream is large – more than 25 degrees. We are continuously monitoring it, and have also reported about its expansion to the Uttarakhand State Disaster Management Authority. So, if something like the Chorabari Glacier Lake outburst happens as we witnessed during the Kedarnath disaster in 2013, then we should be able to save the lives of people downstream,” Dr Sain told News18.
RISING THREAT OF GLACIAL LAKE OUTBURSTS
Glacial lakes form when the vast sheet of glaciers starts melting and the melt water gets accumulated. As the global temperatures rise and climate change intensifies, many of the glaciers have also begun to withdraw at a rapid rate, triggering the formation of numerous such glacial lakes, which, if unstable, can send torrents of water downstream and wreak disastrous floods.
These lakes are also continuously expanding amid changing rainfall/snowfall patterns. Studies show that over a thousand such glacial lakes have formed in the Uttarakhand Himalayas, but their understanding is limited due to lack of adequate ground-based studies.
“We have identified 13 such glacial lakes in Uttarakhand that are moraine-dammed lakes and around ten glaciers which are being continuously monitored, as they may pose threat to people downstream, similar to what we experienced in 2013 in Kedarnath, 2021 in the Rishiganga-Dhauliganga glacial avalanche, and more recently in Sikkim’s South Lhonak Lake,” said Dr Sain, speaking to News18 on the sidelines of the Anil Aggarwal Dialogue 2024 organised by the Centre for Science and Environment (CSE).
GANGOTRI GLACIER RECEDING AT 15-20 MTRS/YEAR
The team of glaciologists at the Dehradun-based institute has been studying changes in the Himalayan glaciers which are not only indicators of climate change, but also to prepare for future disasters. While there are about 9,575 glaciers in the Indian Himalayan Region (IHR) according to the Geological Survey of India (GSI), only 980 of them lie in the north-western state of Uttarakhand and the most sensitive ones are being continuously monitored by the team.
The largest glacier in Uttarakhand Himalayas — Gangotri Glacier with a length of nearly 30 kms — is retreating at a rate of about 15-20 metres per year, said Dr Sain.
“If the retreating continues at the same pace, it will be disastrous. We are studying other glaciers too, but not all glaciers are retreating at the same pace. In the Karakoram region, some are advancing. Therefore, we want to know the fate of the glaciers in the entire Himalayas amid the warming trends and their consequences for people living downstream,” he told News18 on the sidelines of the annual Anil Aggarwal Dialogue 2024.
With the recent spate of disasters, the scientists say the Uttarakhand region is highly stressed — not only on account of activities happening beneath the land, but over it. This has been further intensified by changes due to warming. The need is to do a regular vulnerability assessment of the lower Himalayan region, and step up the monitoring.
“The most vulnerable zones have to be monitored through web-based sensors which can also give information on the health of these glaciers and glacial lakes. Some sort of early warning system is also needed which must integrate the latest tools of Artificial Intelligence (AI) and Machine Learning. We need to learn lessons from the past, and use a balanced scientific approach,” he added.
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