The devastating flash flood in Uttarakhand on Sunday has left everyone surprised. It has killed 18 people and leftover 200 missing. While experts say it is too early to point out what caused the disaster, different theories have emerged, from the incident being a “glacial lake outburst flood” to an avalanche, leading to debris falling in the river. Environmentalists have blamed the disaster on the rapid pace of development in the region and on climate change.
Geological Survey of India, the country’s top to study geoscientific activities, today said the deluge appears to be caused by “glacial calving”.
Dinesh Gupta, the chief of Geological Survey of India said, “Post this devastation, we’ll again constitute a committee as it’s too early to predict regarding the cause of the incident. Prima facie, it’s glacial calving at the highest altitude in Rishiganga and Dahuliganga area and the upper reaches of that.
On Sunday, authorities said initially that the cause was a chunk of glacier breaking off into a river, and later that the trigger may instead have been a phenomenon called a glacier lake outburst flood (GLOF). This is when the boundaries of a glacial lake – formed when a glacier retreats are breached, releasing large amounts of water downstream.
An IIT professor said it is unlikely that it was a cold burst.
Dr. Mohd Farooq Azam, Assistant Professor, Glaciology and Hydrology, IIT Indore said, “It’s a very rare incident for a glacial burst to happen. Satellite and Google Earth images do not show a glacial lake near the region, but there’s a possibility that there may be a water pocket in a lake inside the glaciers, which may have erupted leading to this event…It is unlikely that this was a cloud burst.”
The glacier disaster is a reminder of the monsoon floods and landslides in Uttarakhand in 2013, which killed 6,000 people and led to calls for a review of development projects in the state, particularly in isolated areas like those around the Rishi Ganga dam. Experts have pointed out that the hundreds of power project and widening of roads are playing havoc with the ecologically fragile region which is also earthquake-prone.
Sunday’s occurrence caused a deluge in the Alaknanda river system that washed away hydroelectric stations and five bridges. It also swept away roads and forced authorities to evacuate villages.