New Delhi: There was a hanging glacier that slipped with rock and ice falling from 5,600 metres altitude owing to gravitational pull and this caused disaster in Uttarakhand, as per preliminary observations of experts.
This explanation by scientists comes days after Home Minister Amit Shah told Parliament that initial inquiry has revealed that a landslide triggered a snow avalanche covering approximately 14 square km area and caused a flash flood in the Rishiganga river downstream in Uttarakhand's Chamoli district.
The scientists, however, say it is difficult to comment right now if climate change has been directly responsible for the February 7 catastrophe that washed away two upcoming hydropower stations, claiming at least 34 dead and 200 missing who are feared dead.
Explaining what caused the flash flood, Mohd. Farooq Azam, who is an Assistant Professor at IIT Indore, told IANS in an interview that the Nanda Devi glacier did not burst.
"There is no terminology in science like 'glacier burst'. But we believe that there was a hanging glacier which slipped with rock and ice falling from 5,600 metres altitude," he said.
"To understand if the incident was climate change driven or not, we need to understand how glaciers grow. They have a pattern of snow and melt in winter and summer seasons respectively. This is the normal phenomenon. Now this was a hanging glacier. It is possible that the glacier also collected mass and debris over a period of time.
"We cannot say with confidence right now if climate change had a role to play, but it is possible that the strength of the mass was weakened due to climate driven factors," he explained.
Azam said a team of scientists are at the site in Chamoli district trying to understand what caused this disaster.
"It is early February so temperatures in the area are low and not much melting would be happening right now which could've led to this.
"So far the only explanation is that a hanging glacier cracked due to gravitational pull and the weight of accumulated mass, which resulted in this avalanche.
"However, there is no doubt that global warming is impacting the local climate of the region. The Himalayas are experiencing warmer winters, erratic and extreme rain and snow, more than ever before. These changes are leaving their imprint on the region," said the glaciologist.
"But the mystery which scientists are looking for answers for is what is the source of the water we saw in videos on February 7. Some water will be generated from the heat energy of the fall, but that does not justify the quantum that hit Raini village."
This disaster is a grim reminder of the 2013 flash floods and landslides in Uttarakhand that claimed the lives of thousands of people and animals.
Of course, the effects of such an event can be mitigated by some early warning systems, Azam told IANS.
"When there is a glacier lake outburst flood (GLOF) or flash flood, the only solution is that is an early warning system which can warn communities and authorities to prepare to evacuate people living in these areas.
"Secondly, exposed glacier lakes have a potential to burst and lead to such disasters. But it is possible to pump out water from these lakes. This has been done in Peru and Nepal, where water levels in such glacier lakes are reduced to safe zones to mitigate disaster risks."
On the need to review the policy on 'water grab' dams that put fragile Himalayan ecology in peril, he replied, "Yes, although not 100 per cent sure how climate change effects are being taken into account when environmental impact assessments are done on these dams and other infrastructure projects."
"Natural disasters or climate change induced disasters can harm these infrastructures, so there needs to be better planning for such projects and a review of the present situation of all dams. This lesson should be learnt after this tragedy," he said.
Observing climate change is increasing, Mandira Shreshtha, programme coordinator, HI-RISK Initiative with the International Centre for Integrated Mountain Development (ICIMOD), said: "It is evident that climate change is increasing the occurrence of extreme events in the region."
"Hydrometeorological monitoring is very important. However, the network density in higher elevations in our Himalayan region is poor and much lower than those recommended by the World Meteorological Organisation (WMO). To monitor the changes occurring, we need to strengthen our hydrometeorological networks.
"Satellite data and information in real-time provides some opportunities, however, it has its limitations. In addition to strengthening our monitoring networks there is a need for risk assessments and increasing awareness of the communities living downstream to minimise the adverse impacts of such disasters," said Shreshtha.
The science behind what is currently happening in the Himalayas was forecasted by the Intergovernmental Panel on Climate Change (IPCC) in its 2019 report that said glaciers would retreat in the upcoming years, causing landslides and floods.
Himalayan glaciers play an important role in South Asia, providing drinking water and water resources for agriculture, hydropower and biodiversity.
Glaciers in the Hindu Kush Himalaya region are a crucial water supply for the 240 million people who live in the region, including 86 million Indians, roughly the equivalent of the country's five biggest cities combined.
Another comprehensive report two years ago, the Hindu Kush Himalaya Assessment, coordinated by the International Centre for Integrated Mountain Development (ICIMOD) notes that eastern Himalaya glaciers have tended to shrink faster than those in central and western Himalaya.