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Bhutan's Glaciers: Lunana
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Bhutan's Nature: Glaciers - Glacial Lakes
Lunana's glaciers are melting
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Bhutan's Nature: Glaciers - Glacial Lakes
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Lunana's glaciers are melting
Glacial lake
Eight years ago a glacial lake in Lunana region burst, wreaking havoc down the Punakha- Wangduephodrang valley. After several forays in the area by experts there is still no hope of a permanent solution and the government is making attempts to reduce risks. According to a report published by the International Centre for Integrated Mountain Development ICIMOD and UNEP, 24 out of 2,674 glacial lakes in Bhutan are "potentially dangerous", meaning that they could burst.

Of these eight lakes are in the basin that feeds the Pho Chhu which flooded in 1994, five in the Mo Chhu basin, seven in the Mangde Chhu basin, three in the Chamkhar Chhu basin and one in the Kuri Chu basin. They are all fed by glaciers which are reported to be melting because of "accelerating global warming".

Covering an area of 1,317 square kilometers most of the 677 known glaciers in Bhutan have spawned "many dangerous moraine-damned lakes" which are "increasing in size at a very fast rate". These natural dams may, because of huge amount of accumulated water, suddenly break like the Luggye Tsho that caused the Punakha flood, discharging large volumes of water and debris. Some glaciers are retreating by about 20 meters to 30 meters every year.

While most of the lakes that lie in the Lunana region do not pose an immediate threat, two glacial lakes, Raphstreng Tsho and Thorthormi (Thortomi) Tsho, both at the source of the Pho Chhu, are considered risky, with the latter predicted to burst in 15 to 20 years.The findings were made by numerous expeditions in the Lunana area after the 1994 flood. 

The flood from the Luggye Tsho had apparently damaged the dams of the Raphstreng Tsho and mitigation work on it was undertaken by an Indo-Bhutan team to reduce the "hydrostatic pressure" on the weakened dam in 1996.
The depth of the lake was also partially lowered. However, this particular lake seems to have drawn considerable attention from experts since the 1980s and long after the Luggye Tsho burst in 1994.

Lunana
Glacial lake in Lunana

Although there is no immediate danger, the presence of a peculiar micro - organism on the surfaces of glaciers could accelerate glacial melting and eventually lead to a glacial outburst, according to a preliminary survey report conducted by a Japan - Bhutan survey team which included a glacier - microbiologist, glacio - ecologist and geologist.

Luggye Lake Luggye Glacier Raphstreng Tsho
Luggye Lake Luggye Glacier Raphstreng Tsho

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