Glacial Calving, Climate Change: What Led To The Uttarakhand Disaster?

What caused the devastating flash flood in Uttarakhand on Sunday, that has killed 18 people and left over 200 missing in the hill state? 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 body to study geoscientific activities, today said the deluge appears to be caused by "glacial calving". "Post this devastation, we'll again constitute a committee as it's too early to predict regarding the cause of incident. Prima facie, it's glacial calving at the highest altitude in Rishiganga and Dhauliganga area and the upper reaches of that," said Dinesh Gupta, the chief of Geological Survey of India.

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 glacial 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 cloud burst. "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 the region. Water pockets are lakes inside the glaciers, which may have erupted leading to this event... It is unlikely that this was a cloud burst...," said Dr. Mohd Farooq Azam, Assistant Professor, Glaciology and Hydrology, IIT-Indore.

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 projects and widening of roads is 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.

The Uttarakhand government has made the following helplines for the Disaster Operations Center available to those stuck in affected areas or in need of any help: 1070 or 9557444486.