The surge in Glacial Lake Outburst Flood (GLOFs) in India demands urgent attention and comprehensive measures. As global temperatures rise, the Himalayan region is experiencing accelerated glacial melt, leading to the formation of unstable glacial lakes. The potential consequences are catastrophic, posing severe threats to both human settlements and ecosystems downstream. The existing gap in infrastructure, early warning systems, and preparedness exacerbates the vulnerability of communities in the region. Addressing this issue requires not only regional cooperation but also a holistic approach that integrates climate change mitigation, adaptation strategies, and sustainable development practices. It is imperative for governments to collaborate, invest in research, and implement policies that prioritize environmental preservation, ensuring the safety and resilience of communities facing the mounting risks of GLOFs.
Tags: GS Paper – 1: Geographical Features and their Location; Disaster Management.
The Sikkim story; Glacial lake outburst flood (GLOF); Glacial Lake atlas; Way forward.
India has witnessed at least three highly devastating GLOF events in the Ganga and Brahmaputra basins over the last decade that include the ones at Kedarnath in 2013, Chamoli in 2021 and Sikkim in 2023.
Decoding the editorial: The Sikkim story
- The southern bank of the South Lhonak Lake in Sikkim burst open, leading to an outflow of huge amounts of water.
- Since the lake region is too remote and has scarcely any monitoring network, the exact cause of this glacial lake outburst flood (GLOF) is not known yet.
- The floods caused heavy damage to the Chungthang Dam and hydropower projects of NHPC.
- More than 35 people were killed.
- 14 bridges were washed away or submerged.
- 1,320 houses were severely damaged.
- Drinking water supply lines and sewage networks were damaged.
- Widespread damage to highways was reported in North Sikkim, Gangtok, Pakyong, and Namchi districts. The floods damaged sections of National Highway 10, connecting Sikkim with the rest of India.
Glacial lake outburst flood (GLOF)
- Glacial lakes are formed near the snout of glaciers when meltwater accumulates.
- In recent times, such lakes have been forming with increased frequency because the increased warming of the troposphere has glacier melting.
- The embankments of these lakes consist of loose deposits of glacier moraine, rocks, boulders, soil and ice.
- Since these embankments are not properly compacted, they have a high vulnerability quotient.
- Floods occur when these embankments fail in certain situations:
- The lake water level rises rapidly due to intense rainfall or
- A portion of the glacier is detached from the main body and plunges into the lake, generating high waves. These waves could hit the embankment forcefully.
- Earthquakes destabilise the embankment and water seeping in through the embankment could cause erosion.
Glacial lake atlas
- The ISRO’s National Remote Sensing Centre (NSCRC) released a glacial lake atlas of the Himalayan River Basins.
- NRSC used images acquired by RESOURCESAT-2 satellite during 2016-17 to prepare this atlas, which has identified more than 28,000 glacial lakes of more than 0.25 ha.
- Catchments of the three river basins in north and northeast India have a large number of glacial lakes.
- In a widely quoted scientific paper in Nature Communications, the authors concluded that more than nine million people in High Mountain Asia (HMA), are vulnerable to glacial lake outbursts.
- The Sikkim State Disaster Management Authority has identified more than 300 glacial lakes in the state. Of these, 10 have been identified as vulnerable to outburst floods.
- The Geological Survey of India has found that 13 of the 486 glacial lakes in Uttarakhand are vulnerable to GLOFs.
- A 2021 study led by Delhi University scientist Suraj Mal reported that Jammu and Kashmir has the highest number of vulnerable glacial lakes followed by Arunachal Pradesh and Sikkim.
Different studies use different data and methodologies. Hence, their outcomes are not always comparable.
Threats from GLOFs are likely to increase with time due to global warming. Multi-pronged action is required
- Intense monitoring of meteorological events near the snout of vulnerable glacier lakes is an urgent necessity.
- Data should be gathered at observatories and communicated to a centralised office.
- It should be processed in real-time to forecast the behaviour of glacial lakes and alert people.
- Water levels in rivers downstream of vulnerable lakes should also be monitored continuously.
- A nationwide programme to regularly monitor vulnerable glacier lakes by satellites and drones should be initiated.
- Hydrometeorological information and data gathered through monitoring should be combined to issue forecasts and warnings.
- Infrastructure projects in mountains like dams, bridges and highways, must be subjected to stringent quality control measures.
- Scientific studies on glaciers in the country must be scaled up. Lack of funds and skilled personnel today mean that very few glaciers are monitored.
The Himalayan region requires a comprehensive risk assessment that accounts for projected temperature rise, changes in precipitation patterns, and land-use/cover changes. This assessment should inform disaster risk-reduction strategies.
Frequently Asked Questions (FAQs)
1. What is causing the increase in Glacial Lake Outburst Flood (GLOFs) in India?
Answer: The primary factor behind the surge in GLOFs in India is the accelerating melting of glaciers in the Himalayan region, driven by rising global temperatures. This meltwater contributes to the formation of unstable glacial lakes, increasing the risk of outburst floods.
2. How do Glacial Lake Outburst Floods impact communities in India?
Answer: GLOFs pose a severe threat to communities downstream by causing sudden and massive flooding. These floods can result in loss of life, destruction of infrastructure, and displacement of populations. The impact is not only immediate but also has long-term consequences for the affected regions.
3. Are there specific regions in India more prone to Glacial Lake Outburst Flood?
Answer: Yes, regions in close proximity to the Himalayan glaciers, such as Uttarakhand and Himachal Pradesh, are more prone to GLOFs. The vulnerability is heightened in areas with unstable glacial lakes and inadequate infrastructure for early warning and disaster management.
4. What measures can be taken to mitigate the risks of Glacial Lake Outburst Flood in India?
Answer: Mitigating the risks of GLOFs involves a multi-pronged approach. This includes implementing climate change mitigation strategies, investing in early warning systems, conducting thorough risk assessments, and developing infrastructure that can withstand and manage the impact of such floods. Additionally, sustainable land-use practices and regional cooperation are crucial components of effective mitigation.
5. How can individuals contribute to addressing the issue of Glacial Lake Outburst Flood in India?
Answer: Individuals can contribute by raising awareness about climate change and its impact on glaciers, supporting and participating in community-based disaster preparedness initiatives, and advocating for sustainable development practices. Additionally, adopting environmentally conscious lifestyles and promoting responsible tourism in vulnerable areas can help reduce the overall impact on glacial ecosystems.
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