Living below Nepal’s melting mountains

In an example of local people adapting to the climate crisis with little outside help, the people of Nepal’s Khumbu region are building embankments to protect themselves from increasingly frequent floods coming out of melting glaciers upstream.

While major glacial lake outburst floods (GLOFs) that destroy infrastructure get a lot of press, these local initiatives in remote and high altitude locations do not get much attention.

While on a field survey of the impacts of the 25 April and 12 May 2015 earthquakes on three of Nepal’s potentially dangerous glacial lakes — Imja, Tso Rolpa and Thulagi – local lodge owners in Chukhung village (4,730m) talked of a mysterious flood from the Lhotse Glacier, immediately upstream, on 25 May that year.

The USAID-supported study followed our recently completed High Mountain Adaptation Partnership (HiMAP) program, which worked with communities in the Khumbu and Cordillera Blanca of Peru to develop local adaptation plans of action based on concurrent glacial lake and climate change studies, which were routinely shared with local people.

Further investigation revealed that the source of the Lhotse flood was the interior of the glacier itself, now similar to a massive piece of Swiss cheese, with hundreds of water-filled caves in the shrinking and rapidly ablating glacier. Many of the caves are linked to surface meltwater ponds that can drain rapidly, in some cases triggering the release of water from dozens of conduits that converge to create a major flood.

Photo: GOOGLE EARTH

The 6m high wave generated by the May 2015 flood destroyed the bridge to Island Peak Base Camp and narrowly missed Chukung. It came in the middle of the night and, combined with the memory of the devastating earthquakes the month before, caused widespread panic. Cell phone messages were passed rapidly down the valley.  People from Chukung to Lukla gathered their loved ones and carrying the elderly, ran for higher ground. They feared it might be a massive GLOF from Imja Tsho (5,010m), but in fact it was a smaller flood that impacted only the uppermost settlements.

After the flood, local volunteers in the Khumbu Alpine Conservation Committee decided to begin building a dozen or more gabions, or rock-filled wire cages, immediately next to Chukung, on its southernmost side.

A year later, on 12 June 2016, a second and larger conduit flood from Lhotse occurred, this time headed directly for Chukung. But the flood waters were successfully diverted by the gabions built the year before, resulting in only minor flooding of several lodge courtyards immediately next to the river.  Armed with the knowledge of their successful action, the community continued to devote its resources to construct more gabion walls along the glacial streams that run on the north and south sides of the settlement.

Yet another englacial conduit flood from the Lhotse Nup Glacier occurred a few weeks ago. Once again, there was minimal damage to the village thanks to the new gabions.

With support from the Nepal Mountaineering Association, the Buffer Zone Council, local municipal government and their own resources, villagers have been able to fund and use effective local technology in response to what appears to be a new era of fairly routine flooding from the glaciers.

Such phenomena have occurred for decades, but never with the apparently increasing frequency of the past 10-15 years. Chukung probably should never have been built next to a vulnerable flood plain, but when most of the lodges were constructed 20 years ago, glacier floods happened only every 30-60 years, not every year.

Such floods were so infrequent that in the mid-1950s, glaciologist Fritz Müller was nearly kicked out of the Khumbu by villagers angered over a large flood, most likely from Lhotse Nup Glacier, which destroyed half of Chukung’s grazing land as well as the prayer wheel ghatta at Phunki. They felt Müller had angered the gods by his research activities on the Khumbu glacier.

Fortunately, the then 14-year-old abbot of Tengboche Monastery, the Venerable Ngawang Tenzing Zangpo Rinpoche, intervened on Müller’s behalf and all was forgiven. These days glacier floods happen nearly every year, but they rarely make the national news since they are so much smaller than the major GLOFs that destroy downstream infrastructure, they occur in high and remote locations, and sometimes escape the notice of even local people.

The climate change adaptation demonstrated by Chukung has yet to make global news, but it is one more example of how Himalayan people themselves, with little or no help from the outside, are quietly adapting to the impacts of climate change in real and effective ways.

Bridges are being built higher to cope with more frequent and higher floods. Lodges and new infrastructure are built well above floodplains that until recently were considered to be safe. Many gabions are being built along river banks that only 10 years ago had none.

And life in the high Himalaya goes on.

Alton C Byers, PhD, is Senior Research Associate and Faculty at the Institute of Arctic and Alpine Research (INSTAAR), University of Colorado at Boulder, in the US.