Namgye Chumbi was weeding his potato garden in the village of Phakding in Nepal's Khumbu region below Mount Everest on the morning of 4 August 1985. Because of the monsoon season, there were not too many trekkers hiking up the trail towards Namche Bazaar. It was a brilliantly clear day, unusual for the monsoon season, and he was working by the banks of the Dudh Kosi River. True to its name, the river was milky white and frothing, as the water tumbled noisily over boulders. Yet around two in the afternoon, the river suddenly became strangely silent. The water level went down, and Namgye sensed danger. Much in the same way as coastal dwellers saw the sea recede before the 2004 Indian Ocean tsunami, the Dudh Kosi was about to reveal its terrifying avatar. "I noticed that the white water had turned muddy brown, and in the distance I heard a thundering sound like an approaching helicopter," Namgye recalls. "I looked upstream and saw this huge wall of dark brown water approaching very fast." Namgye indicates the level of the river with his right hand, and raises his left hand high over his head like a cobra to show what he saw.
There was no time to think. Namgye dropped everything and began to run up the mountain. His wife, Sherkima, had more presence of mind, and picked up their two young children, Hira and Tsering, and followed her husband. They reached a ledge as the thunderous flood raced beneath them, lapping at their heels. The ground was shaking like an earthquake, and the sound was deafening. Namgye and Sherkima lost their house and everything in it. If they had been just a few seconds slower, they would have lost their lives as well. Their millet farm upstream was cut in half, as the river changed its course and started flowing through its terraces. Thereafter, the family built a hut, and other families helped them with food. "We only had the clothes we were wearing, but at least we were all alive," he says. Nearly 25 years later, Namgye has built a new house higher up the mountain, where his married children and four grandchildren today live together. The Dudh Kosi, meanwhile, is still frothing white as it flows past the farm. Namgye points out one boulder the size of his house that was brought down by that terrible flash flood.
No one died in the 1985 flood because there were no trekkers on the trails, and people were not asleep in their homes. But it did wash away a large section of the trail as well as all the bridges along this stretch of the river, and the Dudh Kosi deposited debris up to 15 metres high downstream. The water stayed muddy and high for two weeks until it finally started to recede. Villagers in Jorsale and Phakding were puzzled that there was a flood when there had been no rain; they only found out later that a glacial lake called Dig Tso had burst upstream in the Bhote Kosi Valley. A few years later, there was another flood caused by another lake below Mount Ama Dablam that overflowed because of an avalanche; it caused damage upstream but was not as high when it reached Phakding. Nepali glaciologists say there is a glacial-lake flash flood every two years or so on a river in the country, and many expect the floods to become more frequent and more serious as the lakes are gorged by glacial melt. Namgye has heard there are even bigger, more dangerous lakes upstream in the Imja Khola. Is he worried? "I am," he says. "But where can I go?"
Water world
From the air, one can quickly understand why the Himalaya are referred to as the Third Pole. A jumble of ice, rock and snow stretches as far as the eye can see. The frozen flanks rise to breathtaking heights, the cornices on their summits translucent blue against the sunlight. Blocks of ice as massive as large buildings teeter at the edge of icefalls, looking as if their motion has been caught in a snapshot. And like the polar ice cap, all this is defrosting fast. Climatologists say that, like other mountain ranges in the warmer parts of the Earth, the Himalaya are warming three times faster than the rest of the planet. You do not have to be a geologist to spot the signs from up here.