Uttarakhand: Slab Avalanche or Mild Earthquake? Experts Differ on What Caused Uttarkashi Disaster

Days after a major avalanche killed at least 26 climbers from Nehru Institute of Mountaineering on their way back from Draupadi Ka Danda II peak in Uttarkashi district, experts and scientists have made multiple conclusions on the likely cause behind the disaster.

While there is no consensus on what exactly caused the avalanche, most experts have said it is likely the mild earthquake, measuring 2.5 on the Richter scale, that hit Uttarkashi on October 2, two days prior to the incident, as an attributing factor to the disaster.

But the quake was too mild and the epicentre too far away from the avalanche site, Manish Mehta, a scientist at the Wadia Institute of Himalayan Geology in Dehradun noted.

“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,” the expert said. “So it is least likely that the avalanche was caused by the earthquake.”

Another expert noted that the avalanche could have been caused due 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.

At least 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. He also underlined that avalanches cannot be prevented but climbers can take precautions and safeguards against them.

Slab Avalanche

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

Adding to the theory related to quake, 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.

Meanwhile, search and rescue operations were suspended on Saturday due to heavy snowfall. Seven more bodies were handed over to the victims’ families.

Twenty-six bodies have since been recovered and three mountaineers are missing, the institute said. Four bodies were brought down from the base camp on Friday and seven more on Saturday.

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.

(With PTI inputs)

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