Scientists of the Wadia Institute of Himalayan Geology (WIHG) have suggested that a rock mass, weakened due to years of freezing and thawing of snow, may have led to the creation of a weak zone, triggering its collapse that resulted in flash floods in Uttarakhand’s Chamoli district on Sunday.
The scientists made this observation after conducting a helicopter survey of the area to find clues as to what led to the deadly flash floods that swept away everything. So far, the flash floods have claimed 32 lives with over 170 people still missing.
The crashing rock mass also brought earth and mounds of snow with it. The friction may have resulted in heating, which could have caused the floods, the observations suggest.
Kalachand Sain, Director of the WIHG, said the glaciers where the incident occurred feeds the Rishiganga river that finally joins the Dhauliganga.
“This region has a very steep gradient. Our observations suggest that the rock mass may have weakened due to freezing and thawing. This sometimes leads to the development of a weak zone and fractures.
“As the rock mass weakened, the glacier and snow came down crashing, it resulted in flash floods,” he said. The steep slopes of the mountains in the region further increased the intensity of the crash.
Two teams of the WIHG comprising five glaciologists left for Joshimath on Monday to find out the reason behind the incident. An institute under the Department of Science and Technology (DST), the WIHG studies the Himalayan environment and its geology. Sain said an initial report will also be sent to the DST.
In Uttarakhand which has 1,400 glaciers, fewer than 10 are being monitored.
“Of the total 10,000-15,000 glaciers that are situated in India, intense and regular monitoring is done for a maximum 25 glaciers across the Indian Himalayan Region. A minuscule percentage of total glaciers are studied but there is constant effort to increase this number,” SK Rai, a senior scientist with glaciology and hydrology department with WIHG said.
The glaciers being monitored in Uttarakhand by scientists from the Wadia Institute of Himalayan Geology includes Gangotri, Chorabari, Dunagiri, Dokriyani and Pindari, he said.
Sain talked about the challenges of conducting the study with inaccessibility to the glacial regions being the major one.
“All mapping of glaciers has been done through satellite data, but glaciers are all in high-altitude and inaccessible regions, so monitoring those areas automatically becomes difficult. Even if we have large manpower it is difficult to monitor them,” said Sain.
Wednesday, 10 February 2021 | PNS | New Delhi
