Mystery of the Seti river flood

A flash flood on Nepal’s Seti river in early May killed over 70 people and swept two villages away. The area is now swarming with rescuers from government and voluntary agencies, as well as researchers who are still not sure how the flood started. Ramin Sharma travelled to the spot to report for chinadialogue project the third pole.

On May 5, 2012, it was a sunny morning and people were busy going about their business on the banks of Seti river that originates from Annapurna and Machhapuchhre mountains in western Nepal – only about 25 kilometres from the famous tourist city Pokhara and the world-famous trekking route in the Annapurna Conservation Area of the Himalayas.

At about 9.30 a.m., a huge wall of water suddenly rolled down the river, sweeping away two villages. The flash flood killed 71 people, according to local authorities. Only 30 bodies have been found so far.

Almost a month before the annual monsoon hits the southern tip of the Indian subcontinent, and in such clear weather, nobody had expected a flash flood, especially not one of such a dimension. "It wasn’t an unusual day and people were on their business, some were having a bath in the hot springs of Kharapani village when it was completely swept away. Those who were on higher land, out of reach of the flood, had no choice but to keep watching their dear ones crying. After some time they were engulfed by the river," said Tirkhaman Pun, a resident of the village that is no more.

Tek Bahadur Gurung stood next to Pun and kept looking blankly at the river. It had swept away his parents in law, both above 80.

Guman Singh Pun of Valuandi village nearby thought he was watching the end of the world. “Everything looked like it was moving. The swollen river rolled down, leaving behind nothing that was within its reach. We kept looking towards the sky and praying.”

While residents grieve and try to rebuild their lives, scientists from the government, international organizations and NGOs have been debating for a fortnight on how the flood started. The government has said there had been a landslide upstream, the river had backed up behind an unstable wall created by the landslide, and when the weight of the ever-accumulating water burst that wall, the flood came roaring down.

It would have needed a large landslide to hold back so much water, and the government has not explained how such a landslide could have occurred so many weeks before the monsoon, when South Asia gets over 80 per cent of its annual rainfall. There had been no reports of any rain upstream in recent weeks, and this is what makes some scientists and locals believe that the flood was triggered by an avalanche.

There has also been talk that one of the glaciers that feed the Seti may have been receding faster than usual due to global warming, creating a lake at its snout, and that the flood occurred when the walls of this lake gave way. But the possibility of a glacial lake outburst flood (GLOF) – as it is known – was discounted by Pradeep Mool, top glaciologist of the Kathmandu-based International Centre for Integrated Mountain Development (ICIMOD).

“It couldn’t be GLOF but there could be chances of a big avalanche that helped to burst the landslide dam,” Mool told The Third Pole. "It is not easy to confirm a sole causative agent for such damming upstream. There could have been a landslide in the region which is one of the most likely agents for causing such a massive flood. But we cannot deny the possibility of an ice avalanche either."

The experts say there are no big glacial lakes in the Seti watershed, but some locals claim they have seen a big lake in the region long back. “About 30 years ago we used to go up to herd sheep and I saw a big lake in the region at that time. I believe that the flood was due to GLOF,” said Tek Gurung, a resident of Pokhara. But Mool reiterated that ICIMOD scientists had not recorded any lake in the area during their nationwide survey of glaciers. “The debris carried away by the river doesn’t resemble the characteristics of moraine dam and our record show no glacial lakes in the particular area hit by the flood. So it’s not GLOF,” he added. Glacial lakes are usually bounded by moraine, the loose jumble of rock and earth that forms at the snout of a glacier.

Whatever the cause of the flood, its effects will remain for a long time. Today, there are debris piled 15 metres above the riverbank. No wonder the survivors remain scared. Jockey Tamang, resident of Aabang – the first village to be swept away – says, “I was at home and there was this huge sound like a helicopter that’s going to land very close to you.  I was about to get out of the home, when I saw the massively swollen river approaching our home. I screamed and we (15 people from four houses) rushed up the hill and saved our lives.” His aunt could not run fast enough. She was swept away and killed. “We haven’t found her dead body yet,” Tamang said.

The debate on how the flash flood occurred will take a long time to settle. Even a Member of Nepal’s Parliament, Chhimi Lama, believes the flood was caused by a GLOF. “It was probably GLOF and I don’t believe the government’s claim that the flood was caused by a landslide,” he told The Third Pole.

Whatever be the cause, the flood has shown Nepal’s lack of preparedness to handle disasters large or small. It took almost two days before relief workers reached the area, and then the army had to be called in to direct the rescue operations. With the Intergovernmental Panel on Climate Change saying that climate change is going to cause more and more “extreme events”, the country needs to be far better prepared to handle them.

Ramin Sharma is a freelance journalist based in Kathmandu.