Huge Rock Mass Broke from Left Valley of Raunthi Gad, Leading to Flood in U'Khand in Feb: GSI

A huge mass of rock and snow broke from a left valley of Raunthi Gad, crashing down in the Rishiganga valley and triggering a deadly flood in the Rishiganga river that wiped out a hydel power plant in Uttarakhand's Chamoli district in February, a report by the Geological Survey of India has said. According to Saibal Ghosh, Director, Geo-hazard Research and Management Centre, GSI Central Headquarters, the event was initiated by a "snow/ice/rock" mass avalanche, along with a portion of jointed rock mass having an approximate dimension of 400m x 700m x 150m, from the left valley wall of Raunthi Gad. "The energy of impact at a very high speed has pulverised the snow/ice/rock, besides generating melt water, and the entire dislodged material of snow/ice/rock has rapidly flown in the downstream of Raunthi Gad and further down the slope along the Rishiganga valley, causing this huge deluge and impacts to the elements-at-risks exposed across its path, including the formation of a temporary lake on the Rishiganga river just immediately upstream of the confluence with Raunthi Gad," Ghosh was quoted as saying in a statement. The steep higher order streams and the narrow river valleys in the high-altitude areas of the Himalayas remain extremely hazard prone, which are not only vulnerable to Glacial Lake Outburst Flood or Landslide Lake Outburst Flood hazards, but have also become locale for a major disaster caused due to the domino effect of a large or mega landslide or avalanche, it added.