‘77 new glacial lakes in Kumaon Himalayas, can cause flash flood’

DEHRADUN: A field study conducted by a professor of Kumaun University has revealed the presence of 77 new glacial lakes in the Gori Ganga region of the Kumaon Himalayas. The water bodies, situated at an elevation of over 3,500 metres, formed over three decades — between 1990 and 2020 — due to shrinking of snow-covered areas.
The Gori Ganga region mainly consists of Milam, Gonkha, Ralam, Lwan and Martoli glaciers. The largest glacial lake, with a 2.7km diameter, was found in Gonkha. “Any future geological activities can cause the lake to burst, triggering a flash flood,” the study mentioned.
There are several other glaciers, too, which are tributaries of the main glacial bodies, said Devendra Parihar, professor of geography at the Nainital campus of Kumaun University.
“It was found that by the year 2020, a total of 77 glacier lakes (with diameters over 50 metres) were formed. Of these, the maximum, 36 lakes, are present in Milam, seven lakes in Gonkha, 25 in Ralam, three in Lwan and six lakes in Mertoli glacier. Both the diameter of glacier lakes and formation of new lakes are increasing rapidly in all glacier regions,” Parihar said.
The professor told TOI that the Gori Ganga watershed, which was his study area, witnessed severe flash floods in the last 10 years, causing huge losses to property and agricultural lands. The study was conducted using GIS (geographic information system), remote sensing and satellite photographs, which was followed by “ground trothing” (data collection at the site after field trips). The professor also visited Milam and Gonkha glaciers as part of the research.
Due to frequent floods, several villages in the Gori Ganga valley area, including Toli, Lumti, Mawani, Dobri, Baram, Sana, Bhadeli, Dani Bagad, Sera, Ropar, Seraghat, Bagichabgarh, Umadgarh, Bangapani, Devibaghd, Chhodibaghd, Ghattabaghd, Madkot and Talla Mori, have been declared disaster-prone by the district administration.
In November 2021, the year a flash flood in Chamoli killed around 200 people, the Uttarakhand disaster management department had inked an MoU with the Indian Institute of Remote Sensing to carry out a satellite-based mountain hazard assessment, including monitoring of glacial lakes, glaciers and landslides zones and avalanche-prone areas in Uttarakhand. As per an estimate of the disaster management department, there are over 1,000 glaciers and over 1,200 small and big glacial lakes in the higher mountainous region of Uttarakhand.
When glacial lakes burst, they create a glacial lake outburst floods (GLOF), a stream of fast-moving ice, water and debris that can quickly destroy settlements downstream. The Chamoli flash flood is believed to have been triggered by one such glacial outburst. In fact, a high-altitude artificial lake was formed in Chamoli after the flood, possibly by the water that hurtled down the Alaknanda river after the glacier burst.
According to a recent study by a team of scientists from the UK's Newcastle University, 15 million people worldwide are at the risk of flooding triggered by glacial lakes. The highest of those exposed to the threat, around three million people, are from India, followed by Pakistan, Peru and China.