News: Recently, Nepal experienced a catastrophic Glacial Lake Outburst Floods (GLOF) event which caused a flash flood, and washed away a China-built friendship bridge.
About Glacial Lake Outburst Floods (GLOF)
- The GLOFs are flash floods of extreme magnitude that occur when the natural dams, made up of ice, rock debris, or moraine, hold back glacial lakes rupture or are breached.
- These glacial lakes typically form as a result of the melting of glaciers in high-altitude areas.
- Causes: The primary causes of GLOFs include:
- Global warming and glacial melting
- Ice or snow avalanches
- Earthquakes
- Landslides
- Volcanic eruptions
- Internal water dynamics
- Vulnerability of India to GLOFs
- There exist over 54,000 glaciers in the Hindukush-Himalayan ranges which are retreating at alarming rates due to temperature surges in the wake of Climate Change.
- The average temperature in the region has increased by 0.28°C per decade between 1951 and 2020 which has hastened the glacial lake formation as well as the glacial retreat.
- Scientific assessments and studies indicate the higher vulnerability of the Eastern Himalayas to GFOFs as compared to the Western Himalayan region, with the former facing twice the risks than the latter.
- It is contended that the threats would triple by 2050 with more hotspots emerging farther west.
- Steps taken by India
- The National Disaster Management Authority (NDMA) has initiated a proactive shift from mere post-disaster response to risk reduction through its Committee on Disaster Risk Reduction (CoDRR).
- Wadia Institute of Himalayan Geology (WIHG) monitors the glaciers and provides comprehensive analysis of factors that trigger hazards and its associated downstream risks.
- It has prepared glacial lake inventories for Uttarakhand (2015) and Himachal Pradesh (2018), identifying 1,266 lakes (7.6 km²) in Uttarakhand and 958 lakes (9.6 km²) in Himachal Pradesh.
- Central Water Commission (CWC) monitors 902 Glacial lakes and water bodies, to enable the detection of relative change in water spread areas of Glacial lakes and water bodies.
- National Programme: The National Glacial Lake Outburst Flood (GLOF) Risk Mitigation Project (NGRMP) is implemented in four states namely, Arunachal Pradesh, Himachal Pradesh, Sikkim and Uttarakhand at a financial outlay of Rs. 150.00 crore.
- It has one of its components as GLOF monitoring and Early Warning Systems (EWS) including remote sensing data, community involvement for monitoring, alerting / dissemination.
- Two Automatic Weather Stations (AWS) have been installed in Sikkim with further deployments of EWS planned in collaboration with C-DAC, ISRO and Space Applications Centre, Ahmedabad to provide early warning to local communities in case of any GLOF event.
- Risk Indexing of Glacial Lakes: It will be done by the CWC which will involve identifying and ranking lakes based on their likelihood of failure and potential damage they could cause in the event of GLOF.
- Past Examples of GLOFs in India
- The South Lhonak GLOF in 2023 in Sikkim
- Chamoli floods, Uttarakhand (2021)- caused by melting of Nanda Devi glacier
- Chorabari GLOF in 2013, known as the Kedarnath catastrophe
