Kalle Kronholm works on the edge of the world, at the crossroads of science and public safety. Through his company, Skred AS, Kronholm is avalanche consultant to the roughly 2,600 residents of the Norwegian island of Svalbard, at perhaps the most volatile moment in the island’s long relationship with ice and snow. In the past few years, destructive avalanches, mild winters, and a concerned public have carved out a demand for experts like Kronholm. His job: to anticipate how snow hazards will look in a warming Arctic. “You have to take into account,” Kronholm explains, “that Svalbard is one of the places in the world where climate change already has happened most significantly. It comes to play in all kinds of different, weird ways.”
In the insular world of snow and avalanche researchers, there is general agreement that climate change will affect avalanche activity. Exactly how, and by how much, remains unclear. Like the snowflakes which comprise them, no snowpack is exactly alike. They are built of a varying array of layers – weak, strong, thick, thin, continuous, interrupted – and are shaped by wind and weather, undergoing frequent structural changes. And it is this mutable makeup which determines whether a snowpack will stay put, or race down the mountain in the form of an avalanche.
For many scientists trying to forecast avalanches, it all comes back to this: attempting to crack the code of the fickle substance that is snow. Furthermore, climate change means that their research now has very serious implications for human safety and has brought them closer to that other side of snow and avalanche research — trying to protect the humans and infrastructure that lie in the path of new, potential run-out zones.
In the Himalayas, the past five years have been marked by historic calamity. A 2014 avalanche on Mount Everest, killing 16 Nepali sherpa guides, was surpassed the very next year by another avalanche, which took the lives of 19 trekkers and guides. In 2017, in the Gurez valley in northern India, 24 individuals were killed in a succession of four avalanches after days of heavy snowfall.
To study how these events fit into a longer trajectory of avalanche activity is not a simple task, as Juan Antonio Ballesteros-Cánovas from the University of Geneva is only too aware. Data from the long-term pattern of avalanche activity over the last century in the Western Himalayas is, largely, lacking. So when Ballesteros-Cánovas and his team set out to conduct a study on the history, the answer, they found, was on the slopes, by analysing the trees growing on the mountain sides for signs of past trauma—broken branches, missing crowns, bent trunks. Using this information, Ballesteros-Cánova and his team were able to conclude, in a study published in 2018, that avalanches have not only increased in this region in the past decades, but that they will continue to increase.
But, as Ballesteros-Cánovas explains, research does not always equal public awareness. The Himalayan regions are becoming more and more popular with tourists and new roads, homes and businesses are often built without the necessary precautions. Ballesteros-Cánovas says that, in this particular case, everyone from the developers up to the heads of state need to get involved. Scientists, and their studies, can only do so much. “My perception is that the speed of the development is much higher than the speed of the research,” Ballesteros-Cánovas says. “We need to create this awareness in areas where, perhaps, this awareness was not created so far.”
Betty Sovilla spends her time at the WSL Institute for Snow and Avalanche Research SLF (SLF) modelling and studying the dynamics of avalanches. The Swiss town of Davos, where the institute is based, is, of all the places in the world where avalanches occur, perhaps the most prepared for the instability that will come with climate change.
For millennia, alpine villages have been engaged in a rich and ongoing practice of citizen science. At the latter end of World War II, the responsibility for issuing avalanche warnings was transferred from the Swiss Army to SLF. In the years that followed, the group developed a civilian avalanche warning service, which recruited residents of Swiss villages to report on snow conditions for a weekly avalanche bulletin. Locals from all walks of life joined the network: monks, home-makers, farmers, brick-layers. This tradition of avalanche risk management is so rich that, late last year, it was added to UNESCO’s Representative List of Intangible Cultural History of Humanity, alongside the Reggae music of Jamaica, the practice of Korean wrestling, and the nativity scene tradition of Krakow, Poland.
In harmony with their citizens, the universities and institutes of Switzerland, particularly SLF, have long been considered the world experts in avalanche science. From one of their facilities, high in the Bernese Alps, SLF scientists can observe, make measurements on and trigger thundering avalanches. Pick up any significant study on avalanches written over the past 50 years, and you are more than likely to see scientists from the institute listed among its authors. (Kronholm, incidentally, received his PhD from SLF). The software that's used across the world in avalanche risk mitigation, such as RAMMS (which helps analyse the potential impact of natural hazards) and SNOWPACK (which, when fed weather data, simulates the formation of the snowpack), has also been developed by SLF researchers.
In the last few years, however, the nature of avalanches has changed dramatically due to climate change. As global temperatures increase, Sovilla explains, the prevalence of wet snow is likely to increase and with it, the prevalence of wet-snow avalanches. Understanding the dynamics of these types of snowpacks and avalanches, is, therefore, paramount. “More and more in the last year we have realised that we cannot just avoid thinking about what kind of snow is involved in the flow," she says. "It is really the property of the snow that makes the difference in the dynamics.”
Wet-snow avalanches, which remain relatively poorly understood and are difficult for scientists to forecast, are caused by high levels of water in the snow. The water weakens the bonds that unite different layers of snow, and creates instability in the snowpack. Traditionally, these avalanches occur in spring, when warmer ambient temperatures begin to melt the layers of a snowpack. With milder winters, researchers believe, they will become more common throughout the winter.
Lumpy and uneven, wet-snow avalanches look nothing like traditional avalanches, which barrel down mountainsides with a roar at 100 kilometers an hour, under a plume of powdered snow. The wet-snow avalanche looks, on the other hand, like a million tons of cottage cheese flowing down the mountain and into the valley in a slimy, tireless run-out. What they lack in speed and ferocity, they make up for in density and endurance, inflicting great pressure wherever they go and leaving a trail of soggy wreckage in their path.
Johan Gaume, a researcher at the Ecole Polytechnique Fédérale de Lausanne (EPFL) who also completed his doctorate at SLF, is working on a project entitled Snow Avalanche Simulation Laboratory (SLAB). This work builds off some of the modelling techniques that he used when he developed an avalanche rendering that was used in the Disney animation, Frozen. With SLAB, Gaume aims to better simulate the mechanics of wet-snow and wet-snow avalanches.
While still in an early stage of the project, Gaume’s goal is to establish a greater understanding of the snow at a particular location in the mountain. “In terms of mid-term and longer-term effect of climate change on snow avalanches,” he explains “we expect even more avalanches than before because what climate change brings—as we can see now — is a lot of weeks without snow, then a lot of snow at once. A lot more variability — and this variability will bring instability.”
As Gaume points out, the past two winters in Switzerland and its neighbouring nations have been marked by variability. As 2019 began, heavy snows blanketed the Swiss Alps and the Avalanche Bulletin, a twice-daily warning system run by SLF, was painted red with the highest danger level: five, “Very High,” Disaster Situation. In the regions hit hardest by the storms, the SLF reported that there was two to three times as much snow on the ground as was average for mid-January. Some areas reported that, for this point in the season, it was an all-time record. The whole event, the SLF claimed, was a statistical anomaly, “evident only every thirty years or even more seldom”.
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Last year, similar reports were issued. On January 22, 2018, the SLF categorised the avalanche risk as the highest possible danger level over a large area of their jurisdiction—the first time such sweeping classification had been made since the infamous “Avalanche Winter” of 1999. Over the 2017-2018 winter season, the SLF reported 250 destructive avalanches — those causing property damage or injury — in the Swiss Alps alone, and 26 deaths; four fatalities more than the yearly average.
This anomaly has also been observed in the north of Europe. Svalbard has similarly been hit by a succession of unusual, unsettling winters. In 2015, an avalanche swept through Longyearbyen, the island’s most populated town, killing two and injuring several more. In 2017, another avalanche wiped out two buildings and forced the evacuation of another fifty. Kronholm expects that, as the island becomes milder and beset with more precipitation, snow avalanches likes these ones will keep increasing. Meanwhile, slush flows, rushes of water and snow similar to avalanches, which used to occur almost exclusively in spring on the island, now flash through Svalbard’s riverways throughout the winter, too.
As the world warms, it seems that, though they may change in character and frequency, avalanches will remain as capricious and changeable as they are today. “It’s not like making sausages: put a couple of numbers in, turn the crank, and there is a sausage, which looks almost identical every time,” says Kronholm. “I think a lot of us working in this field, we’re really fascinated by the fact that you really have to think. The answer is not absolute.”
This article was originally published by WIRED UK
