“I first went to the power project at Rishiganga. There is only rubble there now, nothing remains. The beautiful Rishiganga seems to have been completely destroyed,” an anguished Atul Sati, an environmental activist and a member of the Communist Party of India Marxist Lennist, said after returning from Uttarakhand’s Chamoli district, which was left devastated by floods on Sunday.

The massive flooding was apparently caused by a piece of the Nanda Devi glacier falling into the Alaknanda river in Tapovan area and bursting through the Rishiganga dam, wrecking the hydropower project there as well as the Tapovan project downstream. As of Monday noon, 19 people have been confirmed dead. Nearly 150 people are missing, according to the police.

At Rishiganga, Sati said the power project workers told him they saw 30-40 people going under the rubble and a few being swept away by the surging waters. Relief and rescue teams dispatched by the central and state governments were trying to find the missing people until late in the evening when low visibility halted their work, he added.

While the Rishiganga project near Raini village has been completely destroyed, Sati said, the larger Tapovan project on the Dhauliganga has also suffered extensive damage.

What happened?

It’s suspected that the floods were caused by a “glacier burst”, about 22 km upstream of Joshimath.

But glaciologist DP Dobhal of Wadia Institute of Himalayan Geology Dehradun said it is “extremely difficult to say what really happened”.

“The local people are telling me that they saw water and silt flowing at high speed for 10-15 minutes in the morning. This is a sign of a big burst. Rubble may have gathered in a lake area of Rishiganga valley, and the water body collapsed because of the avalanche. It is also possible that the avalanche came yesterday or this morning,” he added. “This disaster is similar to the Kedarnath disaster but that occurred during the monsoon and this is the winter season.”

The 2013 Kedarnath disaster, which took nearly 5,000 lives, was caused by flooding in the Mandakini river following a cloudburst.

This week’s disaster could have been even worse had it happened in monsoon when the rivers flow at capacity. In winter, the rivers carry little water and this is what saved areas such as Srinagar, Rishikesh and Haridwar from destruction.

The disaster has again brought under the scanner the dozens of hydel projects being constructed in Uttarakhand. An expert committee set up by the Supreme Court after the Kedarnath disaster had clearly said that hydel projects played a big role in amplifying the scale of natural disasters. Specifically, discussion has focused on hydropower projects rampantly flouting rules, not least in the blasting and disposal of rubble which is seen to have contributed to making rivers more ferocious.

With inputs from Atul Sati.

A version of this report was originally published on Newslaundry Hindi.