ForumIAS announcing GS Foundation Program for UPSC CSE 2025-26 from 27th May. Click Here for more information.
Source: The Hindu
What is the News?
The Geological Survey of India has come out with a report. It suggests that the disaster which hit Chamoli district of Uttarakhand was possibly due to an avalanche.
Note: An avalanche (also called a snowslide) is a rapid flow of snow down a slope, such as a hill or a mountain. Avalanches can happen due to various factors such as increased precipitation or snowpack weakening or by external means such as humans, animals, and earthquakes.
Background:
- In February 2021, a part of the Nanda Devi glacier broke off and flooded the Rishiganga river in Chamoli district of Uttarakhand.
- It led to massive flooding in the region that damaged many villages in its path and claimed at least 72 lives and 200 missings.
- The flood also wiped out two hydroelectric power projects on their way.
Why did this disaster happen? According to the Geological Survey of India report, the disaster happened due to:
- A large mass of snow, ice, and rock avalanche along with a hanging mass of rock had crashed into the Raunthi Garh valley floor.
- Due to this, it crushed the combination of rock, snow, and ice causing a rapid flow downstream of Raunthi Garh and into the Rishiganga valley leading to the flash flood.
- The flash flood, in turn, destroyed the 13.2 MW Rishiganga power plant and damaged the 520 MW Tapovan-Vishnugad hydel power project, in which tunnels several workers had been fatally trapped.
Major Factor behind this Flash Flood:
- A major contributory factor for this flash flood was the unusually warm weather in the region. (heavy snowfall followed by a sudden warmer climate).
- This may have possibly triggered this huge snow and rock avalanche/ landslide, causing a sudden domino effect of flash floods downstream.
Note: The report has found no evidence of a Glacial Lake Outburst Flood (GLOF) having caused the Chamoli Disaster.
