Uttarkashi avalanche triggers debate, experts differ over factors

The recent avalanche near Draupadi Ka Danda-II peak that killed at least 26 mountaineers in Uttarkashi district has triggered a debate among scientists and experts about the contributing factors.

While there is no unanimous view on the possible reasons, most of them feel attributing the avalanche to a mild earthquake that rocked Uttarkashi two days earlier was incorrect.

The tremor, measuring 2.5 on the Richter scale, hit Uttarkashi on October 2. It was too mild and its epicentre too far from the avalanche site, said a scientist at Wadia Institute of Himalayan Geology here.

"The mild-intensity earthquake occurred two days before the avalanche and its epicentre was in a village whose aerial distance from the peak is around 25 km," Manish Mehta, a scientist at the Wadia Institute of Himalayan Geology here said.

"So it is least likely that the avalanche was caused by the earthquake."

One expert attributed the avalanche to higher snowfall in the region.

Snowfall in the upper Himalayan region has been more frequent this time and, due to fluctuation of temperature, fresh snow accumulated on the slopes may be sliding down in the form of avalanches before it can settle.

As many as three avalanches hit the neighbouring Kedarnath valley over 11 days since September 22. Of the three, the latest avalanche occurred just 5 km away from Kedarnath temple at Chorabari glacier on October 1.

But no one was harmed in these avalanches.

"Fresh snow avalanches can be caused even by high-speed winds. Hence, no one can pinpoint one single reason for the avalanche that hit the mountaineers in Uttarkashi," said Uttarakhand Space Application Centre Director MPS Bisht.

Avalanches cannot be prevented but precautions and safeguards can be taken while trekking or mountaineering in the upper Himalayan region, he added.

Nehru Institute of Mountaineering (NIM) Registrar Vishal Ranjan said the injured trainees who were part of the team said it was a slab avalanche.

They said a portion of the ice slab towards which the team was trekking was the first to cave in, he said.

Former NIM principal Col Ajay Kothiyal said slab avalanches usually occurred on slopes.

It happens when constant snowfall causes heavy accumulation of frozen ice, leading to the formation of huge ice slabs, he said while explaining the phenomenon.

These ice slabs come down when fresh snow increases the pressure on them and they come into contact with harsh sunlight, Col Kothiyal said.

Jayendra Rana, who heads the Himalayan Mountaineering and Trekking Association in Uttarkashi, said glaciers weakened by the tremor might have slid under the pressure of fresh snow, causing the avalanche.

Twenty-nine members of a team of trainees and mountaineers from NIM went missing following the avalanche while returning from Draupadi Ka Danda-II peak October 4, the institute said.

It added that 26 bodies have since been recovered and a search is on for the three missing. However, the search operations were hamstrung by heavy snowfall on Friday.