>It is estimated that there are over 8,000 glacial lakes in the Hindu Kush-Himalayan region with more than 200 of them identified as potentially dangerous.

>From 1976 to 2011 there has been an increase of 69 lakes having area more than 0.01 sq km.

> Glacial lakes pose a threat to their downstream communities.

> 292 dams under construction and proposed  in Indian Himalaya. There were 109 proposed dams in the Brahmaputra, 89 in the Ganga, and 94 in the Indus River basins.

Recent scientific studies have reported that no glacial lakes in Uttarakhand are potentially dangerous. But 17th June 2013, Kedarnath glacial lake outburst flood (GLOF) event has created a need to update the analysis of glacial lakes study.  Glacial lake is defined as water mass existing in a sufficient amount and extending with a free surface in, under, beside, and/or in front of a glacier and originating from glacier activities and/or retreating processes of a glacier. Glaciers are believed to have persisted in the Hindu Kush-Himalayas since the last Ice Age (which ended about 10,000 years ago). The Hindu Kush-Himalayan region is one of the most heavily glacierized areas in the world outside the polar regions. Glacier ice covers approximately 33,000 square kilometres in the Himalayan range alone. Thus, explorers, mountaineers, scientists, researchers, developers, and planners, have been attracted to the area for the last 200 years.  The Indian Himalayas have a glaciated area of about 23,300 km2 (Philip and Sah, 2004), cover the northern boundary of India and span from west to east the states of Jammu and Kashmir (JK), Himachal Pradesh (HP), Uttarkhand (UK), Sikkim (SK) and Arunchal Pradesh (AP). Topography, morphology and climate vary significantly. Climate is influenced by the orographic barrier of the Himalayan mountain range in the north–south direction resulting in dry regions in the monsoon shadow. On the other hand, the Indian summer monsoon carries humidity from the Bay of Bengal into the eastern Himalayas but its influence weakens in the western portions of the range (Bookhagen and Burbank, 2006).

With few downstream sites left, hydropower dams are rapidly spreading up Himalayan valleys, closer and closer to rivers’ headwaters, to meet rising electricity demand. Burst or sudden discharge of large volume of water along with debris from these lakes causes glacial lake outburst flood (GLOF) in valley downstream causing massive damage to infrastructure, natural resources and human life.

From 1976 to 2011 there has been an increase of 69 lakes having area more than 0.01 sq km. 18 new lakes grown in 1990 where as this number increased to 29 in 1999 and 31 new lakes were found in LISS 4 imagery of 2011. Very less disappearance of lakes were observed in last 40 years of datasets. The Geological Society of India (2008) published the ‘Glacier Atlas of India’ in order to provide an accurate and up to date metric plan representation of the existing glacier cover for the Indian part of the Himalayas (Raina and Srivastava 2008).

Institutions that could or are undertaking glacial lake outburst floods (GLOF) related activities in the Indian Himalayas include at least the following: 1. Wadia Institute of Himalayan Geology, Dehradun 2. GB Pant Institute of Himalayan Environment and Development, Almora 3. Birla Institute of Technology, Jaipur 4. National Institute of Disaster Management, New Delhi 5. Indian Institute of Tropical Meteorology, Pune 6. National Institute of Hydrology, Roorkee 7. Universities in India.

As glaciers and glacial lakes are related both to water resources and to water-related natural hazards, they need to be mapped and monitored. The challenge is to minimise the risk of outburst and to reduce the vulnerability of nearby communities while securing the potential benefits of the lakes. Scientific information about existing glacial lakes, enhanced by monitoring and early warning systems, and mitigation measures to reduce the impact of glacial melting is essential.

Source: Worni R, et al, Glacial lakes in the Indian Himalayas — From an area-wide glacial lake inventory to on-site and modeling based risk assessment of critical glacial lakes, Sci Total Environ (2012), http://dx.doi.org/10.1016/j.scitotenv.2012.11.043. 

Jack, Rajendra and  Pradeep Formation of Glacial Lakes in the Hindu Kush-Himalayas and GLOF Risk Assessment. International Centre for Integrated Mountain Development, Kathmandu, May 2010.

Amit Anand  PhD Thesis . Glacial Lake Outburst Flood Hazard Assessment In A Part Of Uttarakhand, India  Enschede, The Netherlands [March, 2014]