FORGET Christmas; I’m dreaming of a white February. Seven days of natural snowfall, that’s all I’m asking for while I’m on holiday. Call me a snob if you like, but artificial snow just doesn’t cut it on the slopes. It feels like tiny glass beads under my skis, it’s heavy, and it doesn’t move or pack or stick like the real stuff does.
But we have to be realistic. Reliably snowy Alpine winters are a thing of the past. Our greenhouse gas emissions, including those piling up from flights to Geneva or Boulder, have made sure of that. With global temperatures 1.1°C above where they were on average at the end of the 19th century and still on the rise, the smart money is on learning to love fake snow or else trading in those ski boots for a pair of walking shoes.
Unless, of course, we can engineer our way out of the problem. A new generation of snow-making machines is promising to create artificial stuff that is as good as the real thing, and uses less energy and water to boot.
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Goodbye grainy fake snow, hello year-round fluffy powder. Could this be the answer to all our middle-class winter woes?
As anyone who has ever had their skiing holiday ruined by a dry spell will know, real snow can be capricious. The temperature and humidity have to be just right for any droplets of mist that bump up against airborne dust particles to crystallise upon contact. And the two must meet high in the sky to give the budding crystals time – as they fall – to form the delicate, interconnected branches we associate with snowflakes. It is the air trapped in this branched structure that gives powder snow its signature fluffy finish.
When natural conditions aren’t quite right, ski resorts have a few tricks to spur things along. The most effective is using snow machines that pump water and air out of a nozzle at high pressure. As the air expands, it loses energy, causing a localised drop in temperature. That freezes the pumped water droplets to create tiny airborne ice particles.
These frozen snow seeds are blown high, giving them a little more air time to knock up against a mist of larger droplets also pumped out by the snow guns. When the two meet, the outside of the larger droplets freezes into a hard shell, and an artificial snow “flake” is born. Rather than forming delicate branches, however, these are more like tiny grains of sand, often with a liquid centre as the inside generally doesn’t have enough time to freeze.
While this ersatz snow may sound unappealing, engineer Fabian Wolfsperger at TechnoAlpin, one of Europe’s large snow-making companies, believes there are some upsides. For one thing, it is harder and denser than the real stuff. It is also more homogeneous and packs well into a smooth, even piste. “Those kinds of conditions are what professional skiers are after: they need snow that will resist their hard turns, not just fluff away,” he says.
This fake snow is also good for very steep slopes, where powder is more likely to lead to avalanches, and for giving resorts a solid snow base at the beginning of the season. This is becoming more and more important as temperatures rise. The last few years have seen very dry weather in November and December in Europe, and climate models tell us to expect increasingly erratic conditions. Most resorts make their money between Christmas and New Year, so being able to make a lot of snow on cold days early in the winter is key.
Perhaps it is because I am not a professional skier, but I find Wolfsperger’s argument tough to swallow. An alternative, so-called nature-identical snow, sounds far more appealing. The idea is to produce snowflakes with a classic branched structure and powdery feel.
One method involves running a flow of cold air over a basin of hot water inside a closed chamber. The cold air becomes supersaturated with water vapour, and is blown into a second, cold chamber that is criss-crossed with nylon threads. Ice crystals form on the threads and grow in a typical branching fashion until they are .
The snowflakes are lovely, but the technique can’t replace traditional snow-making, says Martin Schneebeli of WSL Institute for Snow and Avalanche Research SLF in Switzerland. Schneebeli uses the snow to learn about the physics of avalanches in the lab, but the quantities produced in this way are too small to coat a piste.
Michael Bacher of Neuschnee, a company based in Austria, thinks he has found a happy medium. Bacher’s idea combines parts of traditional artificial snow-making with the closed chamber approach. “We are producing high-quality snow, targeting a niche market in the winter tourism industry,” he says.
Slippery slope
Instead of spraying ice nuclei into the open air, he puts them into a tent-like space with air tuned to hold more water than would be possible under normal conditions, with over 100 per cent humidity. This triggers crystallisation on the free-floating ice nuclei. Flakes grow bigger and bigger in this engineered environment, just as in the sky, until they are either blown out the top of the chamber or pulled out through a pipe at the bottom to be distributed on the mountain.
Neuschnee’s method can’t yet handle large resorts. But if it can make the upgrade, it promises to have one further advantage over traditional snow-making: it uses less water per cubic metre of snow formed. With traditional fake snow, some of the water droplets that are sprayed into the air evaporate. Two recent studies – one French and one Austrian – have found that between 15 and 40 per cent of pumped water is lost to evaporation during snow-making, reducing the efficiency of the technique.
“Unfortunately resorts are expanding snow-making, which is like throwing gasoline on a fire”
That can be a problem in high mountain regions where water is already at a premium, particularly with the seasonal pressures of the tourism industry. Large resorts address this by building water storage, says Auden Schendler, vice president of sustainability at Aspen mountain resort in Colorado. “This has several benefits,” he says. “It allows you to fill reservoirs during peak flow, which is least damaging to ecosystems. And it means you’ve decoupled from streams or rivers at low periods, so you are not stressing them.”
By switching to more efficient snow-making methods, resorts could see their water and energy bills melt away, shrinking their environmental footprint in the process. But fake snow is unlikely ever to be without impact. “Unfortunately, in response to climate change, resorts are expanding snow-making, which is like throwing gasoline on a fire,” says Schendler. The more artificial snow we use, the more we heat the planet, and the more of the stuff we wind up needing. It’s all downhill from here.
This article appeared in print under the headline “Accept snow substitutes”
