In a devastating flash flood in the northern state of Uttarakhand in India, at least 32 people were killed and workers trapped in underground tunnels. It also sparked informed speculation about what caused Sunday’s avalanche.
Did an avalanche cause an iceberg to burst? Or could an avalanche or landslide have dammed a river for some time and caused it to flood? Or did ice blocks from a glacier break down due to a rise in temperature?
Rescue efforts continue, with more than 170 people missing – 12 workers were rescued from a tunnel after being trapped in the icy darkness.
Now a team of scientists investigating the incident believes that a piece of a Himalayan glacier fell into the water and caused the great flood in the state of Uttarakhand.
A glacier is a slow-flowing ice river that accumulates snow, rock, sediment and often liquid water.
Five scientists flew over the glacier in a helicopter, took photos, viewed satellite photos and collected data from the devastated area.
According to them, the origin of the incident was a glacier on a remote and inaccessible 5,600 m (18,372 ft) peak called Raunthi.
The scientists believe that part of this glacier was wrapped on a slope and held up by a mass of rock. This part has weakened over a period of time due to freezing and melting.
This piece of ice and rock broke off Sunday and slammed down a steep mountain slope.
When it reached the floor of a valley, they believed that the rocks, snow and sediment had fallen at an altitude of 3,600 meters into a relatively narrow mountain stream.
As the water level in the stream increased, it burst. A surge of water and debris then rushed further by trampling the dam and causing massive floods downstream. Water, gravity and geology conspired to create devastation, leading to numerous deaths and leaving hundreds in danger.
“What we found is actually not very common. The weakening of the ‘hanging’ glacier must have taken place over a long period of time when the ice froze and thawed,” said Dr. Kalachand Sain, director of the Dehradun-based Wadia Institute in Himalayas, said Geology, which sent the team of scientists, told the BBC.
According to him, climate change is the “most important factor” for rapid temperature changes leading to freezing and thawing and ice fractures over time. Glaciers collect snow in winter and lose snow in summer. But as the temperature rises, they lose ice faster than it can collect. Ice melting can lead to the retreat of glaciers.
There are about 10,000 glaciers in the Indian Himalayas. Uttarakhand itself has up to 1,495 glaciers and many are retreating due to the warming climate. “If something as unusual as what happened on Sunday occurs even in 10% of our glaciers, the danger to life and property is great,” said Dr. Sain said.
It is clear that India needs more supervision of glaciers.
