The emerging explanation, according to scientists studying satellite imagery and other data, seems to be some combination of a rock slide and avalanche on the high glacial peaks in the region, perhaps urged on by global warming.
But some villagers in the area suggest the tragedy could be linked to human activity of a different, more clandestine nature.
The locals told the Times of India that the flood waters and debris were accompanied by a pungent smell in the air. As a result, some drew connections to a notorious expedition to the summit of nearby Nanda Devi — the tallest peak contained completely within the borders of India — over half a century ago.
The basic story is that, in 1965, the US Central Intelligence Agency teamed up with Indian forces to install a nuclear-powered surveillance device on the top of the peak in order to keep tabs on China. The expedition ran into a snowstorm on the mountain and was forced to turn back, stashing the plutonium-powered device in a crevice where it could be recovered later.
However, the nuke is thought to have fallen down the mountain in a landslide and has never been seen since.
Now, villagers in the area worry that the long-lost device may be active and emanating enough heat to melt the tons of snow and ice above them.
“If the device is buried under the snow somewhere in the area and is radiating heat, then of course there would be more melting of snow and further avalanches,” Sangram Singh Rawat told TOI.
However, the Indian leader of the expedition, well-known mountaineer Captain Mohan Singh Kohli, later told the Times of India the device was “very unlikely to emanate heat or blow itself up,” even if the case that secures it were to be breached, as it can not be activated on its own.
“The device is most likely trapped among the glaciers. Since it is immobile, it must be lying in a dormant state,” the veteran of the Indian Navy explained. “We spent three years trying to trace it. There is no way it can trigger any untoward incident as the instrument needs other components, too, to be fully operational.”
Meanwhile, authorities are now keep their eyes on a new lake that has formed since the floods, raising concerns that another outburst could again threaten those downstream in the same regions that were struck last week.