Note4Students
From UPSC perspective, the following things are important :
Prelims level: Glacial Lakes
Why in the News?
Since 1977, the South Lhonak Lake, a glacial lake in Sikkim has expanded significantly, growing from 17 hectares to 167 hectares by 2023.
Formation of Glacial Lakes:
- When a glacier melts and retreats, the hollow left behind often fills with water, creating a glacial lake.
- The rocky moraine at the glacier’s end can act as a natural dam, holding the water to form the lake.
- Glacial lakes act as hydrological buffers, regulating water flow from melting ice, which can sometimes pose challenges to downstream communities.
- Glacial lakes often have a vivid blue color, similar to swimming pools, due to the scattering of light by fine rock particles (rock flour) in the water.
- There are several types of glacial lakes, each formed by specific processes and glacier dynamics:
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- Moraine-Dammed Lakes: Formed when moraine debris piles up at the end of a glacier and traps meltwater behind it. These are common and pose risks of outburst flooding.
- Kettle Lakes: This was created when a chunk of glacier ice is buried in the moraine and eventually melts, leaving a depression filled with water.
- Cirque Lakes: Formed in circular basins (cirques) carved by glaciers at high elevations. These lakes are often small and located at the glacier’s original head.
- Pro-glacial Lakes: Situated in front of the glacier, between the ice and the moraine dam. These lakes are sometimes formed when the glacier’s snout melts and deposits water in the valley.
- Tarn Lakes: Formed in depressions left behind in the cirques or basins after the glacier has completely melted.
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Major Glacial Lakes in India
India’s Himalayan region is home to numerous glacial lakes, each with unique characteristics:
- Gurudongmar Lake (Sikkim): One of the highest lakes in the world at 5,430 meters above sea level, fed by glacial melt and known for its religious significance.
- Chandra Taal (Himachal Pradesh): A stunning crescent-shaped lake in the Lahaul-Spiti region at 4,300 meters. It is surrounded by snow-capped mountains and fed by glacier melt.
- Samiti Lake (Sikkim): Located along the trek to Kanchenjunga and known for its clear blue waters and reflective quality.
- Satopanth Tal (Uttarakhand): Found in the Garhwal Himalayas, this lake lies close to Satopanth Glacier and is considered sacred by locals.
- South Lhonak Lake (Sikkim): A growing lake fed by three glaciers, expanding rapidly due to climate change and posing risks of glacial lake outburst floods.
PYQ:
[2019] Consider the following pairs:
Glacier: River
- Bandarpunch: Yamuna
- Bara Shigri: Chenab
- Milam: Mandakini
- Siachen: Nubra
- Zemu: Manas
Which of the pairs given above are correctly matched?
(a) 1, 2 and 4 only
(b) 1, 3 and 4 only
(c) 2 and 5 only
(d) 3 and 5 only |
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