Kedarnath Disaster: Facts And Plausible Causes
Recent climate changes have had significant impact on high-mountain glacial environment. Rapid melting of snow/ice and heavy rainfall has resulted in the formation and expansion of moraine-dammed lakes, creating a potential danger from dammed lake outburst floods1. On 16 and 17 June 2013, heavy rains together with moraine dammed lake (Chorabari Lake) burst caused flooding of Saraswati and Mandakini Rivers in Rudraprayag district of Uttarakhand (Figure 1a).
Prolonged heavy down pour on 16 and 17 June 2013 resembled ‘cloud burst’(except for amount of precipitation of 100mm/h) type event in the Kedarnath valley and surrounding areas that damaged the banks of River Mandakini for 18km between Kedarnath and Sonprayag, and completely washed away Gaurikund (1990masl), Rambara (2740masl) and Kedarnath (3546masl) towns. The roads and footpath between Gaurikund and Kedarnath were also damaged.
There are reports of loss of large number of human lives and damage to the property and livestock. The Chorabari Lake(3960masl) also known as Gandhi Sarovar Lake, is a snow melt and rain fed lake, located about 2km upstream of Kedarnath town which is approximately 400m long, 200m wide having a depth of 15–20m. The bursting of this lake led to its complete draining within 5–10min as reported by the watch and ward staff of the Wadia Institute of Himalayan Geology (WIHG), who were present in WIHG camp at Chorabari Glacier on 16 June and early morning of 17 June 2013. The heavy rainfall together with melting of snow in the surrounding Chorabari Lake washed off both the banks of the Mandakini River causing massive devastation to the Kedarnath town......
.....Our study shows that the main cause of the Chorabari Lake collapse was torrential rains that the area received between 15 and 17 June 2013. Due to heavy rainfall the right lateral basin of the glacier, which is thickly covered by snow (>7 feet thick near the upper part of lake during field work on 4 June 2013) rapidly melted due to rain-water allowing large amount of water accumulation in the Gandhi Sarovar lake (Figure 5b). There were no outlets in the lake, the water was simply released through narrow passage sat the bottom of the lake. Suddenly millions of gallons of water accumulated in the moraine dammed lake within 3 days, which increased their potential energy and reduced the shear strength of the dam. Ultimately the loose-moraine dam breached causing an enormous devastation in the Kedarnath valley ..