In the remote Hongu Valley, nine potentially dangerous glacial lakes have formed in just the last few decades. Because they are so remote, they have received little study. With our 2009 and 2010 expeditions, led by the Mountain Institute and Hokkaido University, we have finally begun the process of studying the physical characteristics of these new lakes. Our latest expedition attempted to navigate the river channel, to see what would be at risk in the event of a catastrophic outburst. This remote route had never been successfully completed by a western expedition, and both previous attempts were met with disaster.Start the Journey »
"When I flew in in '73, you could see the remains of more than half a dozen crashed planes along the sides of the landing strip - the ones that didn't make it." : Dr. Alton C. Byers
With the unpredictable weather, and short airstrip set among the world's tallest mountains, plane and helicopter crashes are still far too common for comfort. During the peak of the tourist season, especially following several days of bad weather when no flights are possible, Lukla often flies in over 200 planes a day.
Namche, hemmed by prayer flags and cyclopic buddhist stuppas, was thirty years ago just a small village, but is now a mecca of hotels, shops, and cyber cafes. A massive flow of tourists, most bound for Everest Base Camp, pass through Namche every year, and the Sherpa people have begun importing most of their labor from the Rai villages of the lower middle hill regions.
In 1985, the Dig Tsho lake burst, destroying a $2 million hydroelectricity plant, laying waste to millions of dollars worth of agricultural fields near Dingboche, and killing several people downstream. We spoke to Sonam Yishi Sherpa, who witnessed the event, and who has become an activist for the control and management of the Imja lake at the head of the valley. Though this lake has been studied extensively by research teams over the years, their findings are rarely shared with the local people, leaving many in a state of apprehension and uncertainty. The Mountain Institute hopes to improve this situation with its South-South Collaboration program.
Working in the mountains isn't easy. Trapped in a 4-day snowstorm, four out of our six-member team had to descend to lower altitudes with altitude illness; one was flown out to Kathmandu by helicopter. Altitude sickness can turn fatal if proper care isn't taken to acclimatize properly, and even then one must proceed with great care.
When Erwin Schneider visited this site 50 years ago, what he saw was a large glacier. Now there is a vast lake, over a square kilometer in size, holding 35 million cubic meters of water. The old glacier is melting and receding at a rate of 17m per year. Poised above the upper and lower Khumbu regions with its growing population centers, an outburst could be devastating - but is it dangerous? Despite all the research, experts can't seem to agree, and as yet there have been no steps towards lake control (i.e., lowering the depth) or management (i.e., use of the water for beneficial purposes, such as irrigation or hydropower).
Last year, our expedition crossed over the 5800m Amphu Lapsa pass using fixed rope and ice axe, to descend directly into the Hongu valley. This year, due to the heavy snowfall, we were forced to take the long way around: back down to Lukla, then east towards the 5400m Mera glacier.
"It was 5AM when I heard the sound... the water was rushing towards us from the lake, crushing boulders together so sparks flew, and the air smelled like gunpowder..." : Lakpa Sherpa, lodge owner
The town of Tagnag was struck by a glacial lake outburst from the Thame Pokare Lake in 1998. Luckily, a hill kept the water from destroying the whole village, but several hotels and houses were completely destroyed, and downstream several people were killed. The once-fertile valley was reduced to a ragged field of rocks and boulders. The approximately 1 km square lake, having spent its energy, is no longer a danger today, but Lakpa worries for the inhabitants of the lower Hongu valley, with nine newly formed glacial lakes looming above it.
To enter the Hongu Valley requires climbing over the 5400m Mera Glacier. Even here, the effects of tourism are apparent: last year, our expedition carried out 30 bags of trash from this area. When we returned this year, it was almost as bad as it had been just a year ago. This is only one example of a growing trend: as tourism increases every year, trekking groups and locals alike are leaving heaps of garbage in their wake.
Camped in the Hongu Valley, we were now directly in the path of all 9 glacial lakes. At night, furious winds whip the tent, and avalanches rumble in the distance. We huddled in our bags at -15 degrees, hoping that the last rumble wasn't the bursting of a huge and swollen lake's terminal moraine...
The Hongu Valley is remote and uninhabited, but 40 kilometers down its river channel lies major villages and agricultural fields. Are they in danger? After studying the lakes, we were trekking down the river channel to find out.
Just to reach the lakes requires building a bridge across the Hongu River, racing the raising water level as glaciers feeding the river melt away in the afternoon. After that, we had to trek up the massive debris fields and scree slopes on the lateral and terminal moraines surrounding the lakes, composed of loose boulders and slippery rocks.
hamlang is considered by many people, from scientists using remote sensing technology to local herders, to be the most dangerous lake in the entire valley, but is it? Our first expedition rowed out onto the lake in an inflatable raft to do the first bathometric surveys on the lake. This, combined with our other on-site analysis, shows that it may be less of a threat than anticipated - especially compared to its completely unknown neighbor, Lake 464.
Unnoticed by remote sensing due to the shadows cast over it by Chamlang Peak, this lake is so new and remote that it doesn't even have a name. As we gazed at the vast waters, the massive blocks of overhanging ice, and the all but nonexistant terminal moraine, one thing was clear. This lake was a ticking time bomb, and it could go at any time.
The next phase of our journey was the most difficult, and the most unknown. The trek down the river channel had only been attempted twice in the last 60 years: by Erwin Shneider in the 60s, and Jack Cox in 1995. Both groups got lost in the jungle, nearly starving to death. Schneider's expedition, delirious with starvation, were forced to eat the leather headbands of the porters to survive.
Cox, after belaying down a cliff, reported being saved only by the apparently supernatural intervention of his Sherpa sirdar, or leader, who attempted to jump at least 10 meters across the raging river to fix a rope on the other side. Just as he was clearly descending into the deadly rapids, he appeared to levitate up and over the remaining 5 meters to the boulder, where he lay down and promptly fell asleep for 30 minutes. When he awoke, he was able to catch a rope thrown to him from the other side, thus enabling construction of a bridge that became the expedition's path to safety.
Now it was our turn.
On our second day we ascended over 1000 vertical meters, from the subtropical jungle back into the subalpine. After 10 hours of trekking through icy boulders and rhododendron thickets, our campsite was nowhere to be found. We were losing light, and our guide, an old Rai man who claimed to have walked the route before looking for the valuable Yarsa-Gumba plant, was hours behind. Uncertain whether we were even on the right path and unable to continue, we were forced to camp in a mountain cave, collecting dripping water from the overhanging rock.
Climbing to the high ridges alongside the channel, we found a pile of stones: we were on the right path! Gazing down into the impenetrable thicket of the Hongu river below, one thing was clear: the river channel is incredibly narrow all the way down to its confluence with the Dudh Kosi river. Water from a GLOF would actually accelerate in such a narrow channel, increasing its velocity and damage on the settled lands below.
From here, we could actually see the reflections on the tin roofs of the village we were attempting to reach - but distances are deceptive in that thin air. It would take us still another 3 days to reach civilization.
Finally emerging to civilization, we were met with dancing and celebration, courtesy of the staff of the Makalu-Barun National Park and Buffer Zone, which my family helped to establish in the mid-1990s. The people of Bung hope the route we had completed can be developed and turned into an adventure tourism trek, bringing money into their village.
We also witnessed a great deal of development, agriculture and houses, directly along the river channel, especially in its lower reaches and confluence with the Dudh Kosi. In the event of an outburst, much of this region would be completely destroyed.
Climbing into a shaky twin-otter plane, we reflected on what we had learned. A critically dangerous lake - a narrow river channel - villages and agriculture under threat. But what can be done? The region in which the lakes are located is extremely remote, working conditions at high altitudes are difficult at best, and any kind of management in such a remote setting would prohbitively expensive.
Or would it? The men and women of the Peruvian Andes, where tens of thousands have been killed by GLOFs, have managed their own lakes for the last 50 years, at a fraction of the cost of first-world projects. The Mountain Institute plans to bring Peruvian glaicologists and social scientists to Nepal next fall to work in collaboration with their Hindu Kush-Himalayan colleagues concerned with similar issues. Perhaps, working together, a solution is possible.