Glaciers in Bhutan

[1] On 7 October 1994, a GLOF from Luggye lake (part of Lunana glacial system) led to over 20 fatalities in Punakha.

[1][5] In 2011, ICIMOD recompiled its data-set for the entire Hindu Kush, using an automated classification of satellite imagery from 2005 ± 3 years in combination with digital elevation model — the area was revised to 642 km2 (based on Bhutan's new national boundary).

[1] The "valley glaciers" are located along the southern flanks of the main topographic divide of the Bhutan Himalaya, and are characterized by debris-mantled snouts.

[9][7] A 1999 publication, deriving from satellite images, maps, and survey data, reported the retreat of multiple glaciers in the Bhutan Himalayas.

[8] A 2.5 C increase in regional temperature over the next century (as predicted by IPCC) will reduce glaciated area by half and bring meltwater discharges to negligible values.

[9] It recorded a drastic reduction in mass to the extent that no accumulation zone existed at all, and the observations were in agreement with the 2012 model.

[2] From 1980 to 2010, net area had roughly shrank by 23%; absence of debris and presence of a glacial lake at snout accentuated these retreat rates.

[9] Changes in river runoff, global sea-level rise, and increase in frequency of glacial lake outburst floods are probable.

[9][7] Decrease in meltwater discharge directly affects the viability of hydroelectric power production, which is one of the economic lifelines for Bhutan.

[18] For public safety, these glaciers and glacial lakes are maintained by the Ministry of Economic Affairs' Department of Geology and Mines, an executive (cabinet) agency of the Government of Bhutan.

[19] The department, as part of its environmental "mitigation projects," aims to lower the levels of glacial lakes and thereby avert GLOF-related disaster.

[20] The Department uses silent explosives and other means it considers environmentally friendly in order to minimize the ecological impact of its mitigation projects.

These projects, however, remain difficult to conduct because of the weather, terrain, and relative lack of oxygen at the glacial lakes' altitudes.

As of September 2010, GLOF early warning systems were slated for installation by mid-2011 in Punakha and Wangdue Phodrang districts at a cost of USD 4.2 million.