Uttarakhand flood: Lake formed as stream joining Rishiganga gets blocked
What's the story
The debris brought by the avalanche in Uttarakhand earlier this week has blocked a stream that joins the Rishiganga river forming a temporary lake which if breached can cause further damage. The Central Water Commission said, "An artificial lake has formed on river Rishi Ganga in Chamoli district, Uttarakhand, with length 350 meters, height 60 meters and a slope of 10 degrees."
Twitter Post
CWC shared a video of the lake
An artificial Lake has formed on river #Rishiganga in #Chamoli Dist #Uttarakhand with length of 350 m height of 60 m with slope of 10deg. Video showing the lakse is uploaded. pic.twitter.com/nNRzVrExlX
— Central Water Commission Official Flood Forecast (@CWCOfficial_FF) February 12, 2021
Information
Avoid going to the banks of the river: Chamoli administration
The Chamoli district administration issued an alert asking people to avoid going to the banks of the river. The glacial lake has formed on the confluence of Raunthi Gad and Rishiganga. Uttarakhand Chief Minister Trivendra Singh Rawat asked people not to panic but maintain caution.
About the lake
We are researching more about the lake: WIHG Director
According to Wadia Institute of Himalayan Geology Director Kalachand Sain, a team of scientists from the institute conducted an aerial survey of the upper reaches of the Rishiganga just a day after the Sunday avalanche and spotted the new glacial lake there. "The recent avalanche has led to its formation in the higher stretches of Rishiganga's catchment area," he said.
Further statements
The lake may lead to further damage: Sain
According to the report by WIHG, the assessment of the actual magnitude of risk involved due to this impoundment of water requires a detailed survey. "The catastrophic floods on Sunday also brought sediments in the Rishiganga River. Since the width of the river is very less in the upper stretches, the sediments have blocked a stream resulting in a lake," Sain said.
Information
Details about the avalanche that happened earlier this week
A portion of the Nanda Devi glacier broke off in Uttarakhand's Chamoli district on Sunday, triggering an avalanche and a deluge in the Alaknanda river system that washed away hydroelectric stations and endangered lives of people living along the banks.
Scientific details
What caused the avalanche and later resulted in floods?
According to WIHG, a mass of rock weakened over a period of time due to freezing and thawing of snow must have led to the creation of a weak zone triggering its collapse which brought down sediments. The avalanche was accompanied by thick snow. This resulted in the formation of a temporary dam that eventually breached, causing deadly floods in Chamoli district on Sunday.
Further details
Steep mountains increased the intensity of the crash
The incident occurred adjacent to Raunthi glacier. The area has glaciers that feed the Rishiganga river, which ultimately joins the Dhauli Ganga. The steep slopes of the mountains increased the intensity of the crash. The stretch of the avalanche was about three kilometers with an average slope of 37 degrees, before reaching the Raunthi Nala/Gadhera floor at an altitude of about 3,600 meters.
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A team of Geological Survey of India will make inspections
Chamoli District Magistrate Swati S Bhadauria said, "An eight-member team of the scientists of the Geological Survey of India has been formed to inspect the lake and submit its report to the district administration at the earliest."