IT WAS a close encounter with death that changed John Reynolds’s life. He describes how, as a young geography student on a field trip in northern Norway, he watched helplessly as a glacial lake burst its banks and a wall of water rushed down the valley towards him. “I was stranded on one side as the flood made a 10-metre-wide gap in the road. The rest of the team was on the other side. Suddenly one of them shouted to me to get back. I was within seconds of being washed away as the road disappeared beneath my feet. I ended up just a metre away from the edge. It would have been the end for me.”
Instead, it was the beginning of a lifelong obsession that has made Reynolds probably the world’s greatest expert on these glacial time bombs and how to evaluate and defuse them. Today he knows that the power of a bursting lake can be awesome, throwing huge boulders long distances. “Much of the water moves down the valley in a single gigantic wave carrying everything in its path,” he says. In a constricted valley, the wave doesn’t dissipate, but keeps on going, sometimes for hundreds of kilometres. In 1964, for example, when a glacial lake in Tibet burst and destroyed a highway, trucks from the road turned up 70 kilometres away. During the 20th century, around 32,000 people were killed and millions of dollars worth of infrastructure such as roads and hydroelectric plants were destroyed by glacial disasters, many of them involving bursting lakes.
Reynolds’s dire warning is that things are set to get much worse. As global warming gathers pace, thousands of glaciers that grew during the “little ice age” from 1500 to 1800 are melting fast and creating their own lakes. Recent estimates suggest there are 1500 glacial lakes in Peru, 2000 in Nepal and nearly 3000 in the tiny Himalayan kingdom of Bhutan. There may be 800 more in the Italian Alps alone. Nobody has got round to even estimating the number in Pakistan, India, Tibet, Kazakhstan or Bolivia. Most are not an immediate hazard. But earlier this year a report from the UN Environment Programme (UNEP) named 44 glacial lakes in Bhutan and Nepal “that are filling so rapidly they could burst their banks in as little as five years’ time”. The report’s author, Surendra Shrestha, warned: “These are the ones we know about. Who knows how many others elsewhere in the Himalayas and across the world are in a similar critical state?”
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Although the water from melting glaciers often simply runs down to the sea, in many cases the valley below is dammed by a pile of debris, or moraine, deposited at the glacier’s end before it began retreating. These unstable moraines can be more than 100 metres high and hold back a meltwater lake several kilometres long. Potentially catastrophic lakes can form from nothing in less than five years. “Often the first time the existence of a lake becomes apparent is when it floods communities downstream,” says Reynolds. “In the 1950s we had about one burst a decade. In the 1990s, it was three a decade. By 2010 I think we will be talking about one every year.”
Reynolds predicts that the 21st century could see hundreds of millions dead and tens of billions of dollars in damage. The problem is made worse because more and more people are living in the narrow valleys beneath the lakes. And they are being joined by increasing numbers of tourists, usually oblivious to the threat as they marvel at mighty glaciers reflected in the crystal waters.
Methods of assessing the risk of these lakes bursting are often crude, says Reynolds. “Many supposed experts, including some working for UNEP, seem to just go looking on satellite images for water, and when they find it, pronounce it unsafe. Then they depart, leaving local people in sometimes quite unnecessary fear.”
The most dangerous lakes, says Reynolds, are ones that have a high but narrow moraine with water almost to the brim, perching precariously above a steep valley. The moraine may be leaking or contain a block of ice that could melt, making a hole in the dam below the water line. Most dangerous of all, there may be an unstable bank or a cliff of melting ice that could fall into the lake, causing a tidal wave that would breach the moraine.
Reynolds, who runs a geological consulting company in north Wales, has been heavily involved in efforts to identify and stabilise dangerous lakes in both Peru and, more recently, the Himalayas. He claims part of the credit for saving the lives of some 25,000 people in 1989. He negotiated emergency British aid to airlift in siphons to lower a Peruvian glacial lake beneath the Hualcan glacier as a block of ice in the moraine melted, threatening the town of Carhuaz, nestled in a valley 2000 metres below. “We probably had less than two months before disaster struck,” he says.
That particular operation was a success, but sometimes trying to solve the problem can make it worse. “One of the biggest hazards,” says Reynolds, “is botched attempts to empty dangerous lakes, especially by digging a channel or tunnel through the moraine.” In 1993, Reynolds returned to the Hualcan glacier to watch Peruvian engineers dig a tunnel to lower the lake by a further 20 metres. He realised that the water pressure in the tunnel during the discharge would be so great that the moraine would burst. His solution was to dig a series of tunnels to lower the lake in five-metre stages, reducing the pressure on the moraine. The inhabitants of Carhuaz were saved for a second time.
Other efforts have been less fortunate. In 1950, Peruvian engineers were draining Lake Jancarurish at the toe of the Kogan glacier. As the water level dropped, a tongue of ice that had been floating on the water surface was left in mid-air and broke off the glacier. The crash sent a giant wave across the lake, bursting through the moraine. Some 10 million cubic metres of water flooded into the valley below. Around 500 people, mostly project workers, were drowned.
Reynolds fears that a combination of poor survey work and short-sighted engineering could lead to an even worse disaster in Bhutan. The Lunana valley – on the route of the popular “snowman trek” – contains probably the most perilous complex of glacial lakes in the Himalayas. It includes Thorthormi and Raphstreng, two particularly fast-growing lakes. Thorthormi is 65 metres vertically above Raphstreng and held back by a moraine less than 30 metres wide. If the moraine breaks, Thorthormi will pour into Raphstreng, sending the water from both lakes crashing down the valley. “Around 48,000 people live in the valley downstream. Whole communities would be drowned,” says Reynolds.
Photographs reveal the moraine may already be shifting. And Reynolds claims to have uncovered evidence, missed by Austrian scientists who surveyed the moraine three years ago, that water is already seeping from Thorthormi into Raphstreng. Recent engineering may be to blame. Two years ago, Indian engineers dug a drainage channel to lower the water in Raphstreng. “My big fear is that by lowering the water level they may have destabilised the moraine,” says Reynolds. “I wouldn’t be surprised to see a Reuters report of a disaster there within a year.”
If it does happen, a catastrophic outburst at Bhutan’s Lunana lakes will send lethal floods across the border into India. This raises the issue of who should pay for any engineering solution to such problems. Bhutan and India enjoy reasonably good relations, but in other regions of the Himalayas where a glacial outburst in one country threatens people in another, the situation is potentially explosive in political terms. An incident in Indian-held Kashmir, for instance, might kill thousands in Pakistan. Scandalously, glaciologists can only guess at the risks for the moment because India recently refused a UNEP research team permission to survey its Kashmiri lakes, on account of security fears.
Around the world, governments are slowly waking up to the danger lurking in the mountains, but even where there is a will to act, the backlog of basic survey work is huge. Nowhere is this more apparent than in Peru, where many large towns lie directly in the path of potential devastation. Peru’s state-run hydroelectric company, Electroperu, has drained some 40 lakes in the past half-century and there have been no deaths from lake bursts since 1972. However, it disbanded its mountain safety unit six years ago, following privatisation. Although the unit resumed work less than a year ago under government control, the glaciologist who ran the old survey team, Cesar Portocarrero, warns: “We no longer have the glacial lakes mapped. New lakes are forming all the time, so the risk of another big disaster grows.”
And glacial meltdown brings other problems besides catastrophic floods. Along the length of the Andes, from Colombia to southern Chile, the disappearance of glaciers will soon mean dwindling supplies of hydroelectric power and water, according to Lonnie Thompson of Ohio State University. Cities under threat include the Ecuadorian capital, Quito, which is watered by a glacier on Antisana mountain that has shrunk by a third in 40 years, and the Peruvian capital Lima, which depends on glacial meltwater to maintain the River Rimac’s year-round flow across the coastal desert. “In Bolivia, water supplies for half the country’s population are threatened if the glaciers disappear,” says Bernard Francou of the Paris-based Institute for Development Research, who predicted in a study published last year that 80 per cent of the country’s glaciers would be gone by 2020.
It’s a similar story in the Himalayas. The Gangorti glacier at the head of the River Ganges, for instance, is retreating at a rate of 30 metres per year. Today, the extra meltwater each spring brings floods downstream. But as the glaciers begin to disappear in the coming decades, the river flows will become less reliable and eventually diminish, bringing widespread water shortages, according to Syed Hasnain of Jawaharlal Nehru University in Delhi, who has studied the glaciers for the International Commission on Snow and Ice. Dry-season flows of water sustained by Himalayan glaciers could be gone in 30 years.
Many of Europe’s great rivers such as the Rhine, Rhône, Po and Danube also rely partly on glacial meltwater to sustain their summer flows. Researchers may eventually conclude that the floods in central Europe earlier this year had as much to do with fast-melting glaciers as heavy rains. But, says David Collins from Salford University, “when all the ice goes, the summer flow of the rivers will be almost entirely dependent on rainfall. And under global warming, rainfall in southern Europe is set to reduce”.
In the Alps, tourism is already suffering as a result of glacial meltdown. Austrian ski resorts, including KitzbĂĽhel and Zell-am-See, are close to being abandoned because of insufficient snow. In Switzerland, St Moritz and Klosters could soon lose their lower pistes. Some resorts have already shut down, and at many others the skiing season is weeks shorter than it was just a decade ago.
Of course, the root of all these problems is global warming, and the decline of Europe’s ski industry seems inevitable unless we can reverse the warming trend. But Reynolds points out that we already have the know-how to alleviate some of the worst effects of glacial meltdown. Proper engineering of potentially dangerous lakes can both save lives downstream and turn the lakes into dependable sources of energy and water. Electroperu has in the past few decades converted several dangerous lakes into safe economic assets by replacing their unstable moraines with concrete dams. In essence, the world’s frozen water towers could be gradually replaced by reservoirs in this way. And Reynolds sees this incentive as the way to inject investment into saving lives in the mountains.
The idea of holding even more water in the mountains might sound foolhardy, but with good glaciology to ensure no unpleasant surprises, it’s perfectly possible. “We have the expertise to prevent deaths from glacial lakes,” says Reynolds. “The trouble is we so rarely get the chance. I keep scanning the headlines fearing the next disaster.”
Going, going, gone
Ptolemy called them the Mountains of the Moon. Today the Ruwenzori, straddling the border between Uganda and the Democratic Republic of Congo, are more prosaically known as the highest range in Africa, with 10 summits over 4800 metres.
Wet, cold and haunting are the adjectives that come to my mind as I negotiate the steep slippery rock on my climb to the Elena Hut near the top of the highest peak, Mount Stanley. I feel like a cross between a tightrope walker, a ballerina and Spiderman when ascending the most precarious sections. As the air thins, I find myself having to pause more often to catch my breath. A billowing fog lifts and I see the Stanley Glacier towering above me. Suddenly, there is a spectacular panoramic view across the wide Bujuku valley towards Mount Baker and Mount Speke.
But this is not the scene I had expected. I have seen pictures taken in 1906 by Italian photographer Vittorio Sella, who accompanied the Duke of Abruzzi on the first ascent of Mount Stanley. Sella’s photos were of an alpine wonderland dominated by snow and ice. Speke Glacier, for example, dropped off in a sheer 30-metre ice cliff and one of Baker’s Glaciers took the form of a soaring letter Y. Now I see mostly rock. Perhaps it’s an optical illusion, the mountain sunlight playing tricks again, or maybe it’s just my physical fatigue. Only later do I learn that the glaciers of the Ruwenzori are in rapid retreat.
When the Duke of Abruzzi and his party made their historic ascent of Mount Stanley, they had to hack a near-vertical passage through huge, bulging cornices of icy rime to reach the snow-covered summit. As recently as 1960, mountaineers classed this direct ascent as “grade III to impossible”, depending on the state of the cornices. These days, such cornices scarcely form at all, while the peaks themselves are just bare rock, according to Henry Osmaston of Bristol University in England and colleague Georg Kaser from the University of Innsbruck in Austria, who have been documenting the glacial extinction on the Ruwenzori for over a generation.
A century ago all the mountains in the range contained substantial glaciers. Today, there are none on Mounts Emin, Gessi and Luigi di Savoia. The few remaining glaciers on the higher summits of Stanley, Speke and Baker cover barely a quarter of the area they occupied back then. The Elena Glacier on Mount Stanley, for example, has retreated 200 metres up the mountain as a result of rising temperatures and deposits of ash and dust from dry-season bush fires on the plains below. Osmaston and Kaser forecast that if the present rate of global warming continues the glaciers of the Ruwenzori could be completely melted by 2025.
The speed at which all this is happening is terrifying. Yet, high on Mount Stanley, global warming seems very remote. As I approach the Elena Hut, snow begins to fall in the first flurries of a blizzard that will later foil my attempts to reach the summit. It is bitterly cold. That evening I huddle inside the hut with every stitch of warm clothing on and a bowl of hot soup in my hands, watching my first snow storm in equatorial Africa.
Curtis Abraham