This Is Why … it stings when you ski through a blast of fake snow

My little Jozo Weider racer, in her first ever away race earlier this season. Photo by Rob Tankovich, Head Coach, U10 program

It’s coming to the end of ski season in this part of the world, which makes at least two members of my household incredibly sad. With the forecast for the week ahead projecting several days with highs above zero degrees Celsius, the local area ski hills will be making as much artificial snow as they can in the evenings when it gets colder. Ideal temperatures for making snow is about ‒5 to ‒10⁰C (cold enough to produce lots of powder, but not too cold that the water freezes in the hose before getting to the snow gun). Humidity is also a factor …. snowmaking needs less than about -2⁰C and 50% humidity to really work. A bit of natural snow falling is also helpful.

Water and high pressure air are pushed through the nozzles of the snow gun at high speed. The air expands as it comes out of the nozzle, dropping in temperature, quickly turning the fine water droplets into tiny ice crystals. These serve as seeds or nucleation points for more water droplets to accumulate and freeze, forming snow as they fall to the ground. The hang time is only a few seconds, so conditions have to be just right for the end result to be skiable. There definitely isn’t enough time to form the classic and elaborate flakes we usually picture, so the snow that falls is icier and more pellet-like than the stuff from the heavens and boy, does it sting a little when you ski through the blast from the guns! Once decent piles (called “whales”) have accumulated, groomers move it around for optimal coverage.

“Whales” forming with snowmaking at full blast (“IMG_8995” by V31S70 is licensed under CC BY 2.0)

Snowmaking was first discovered by a team of Canadian scientists in the 1940s, led by Dr. Ray Ringer. The team was attempting to study icing on jet engines, but they found that they were very good at filling their wind tunnel with snow instead of ice when they sprayed fine water droplets into the air. Their scientific paper formed the basis of the US patent filed in by Tey Manufacturing (Milford, Connecticut) in 1954. The technology has evolved considerably since the 1950s.

In addition to state-of-the-art snowmaking, some resorts in the Alps have been attempting “snow farming” in recent years, as the ski industry continues to wrestle with climate change and the impact on their bottom line. Using the great thermal insulating properties of sawdust over the snow, as well as reflective tarps, resorts are finding that they can start their season a little earlier the following year if they can keep it all from melting during the warmer off-season. For example, Davos in Switzerland has been using sawdust coverings, estimating that they can save 70 to 80% of their snow volume this way. Would this work in Ontario? Not likely – Davos has much cooler summers than we do, with typical peak summer highs of only about 20⁰C.

Snowmaking isn’t just about getting a few more runs on the slopes early/late in the season – a team from the Netherlands, led by renowned glaciologist Hans Oerlemans, has been experimenting with using snow cannons to protect glaciers in the Alps that are melting rapidly due to climate change.

In October 2019, Oerlemans was awarded 2 million Swiss francs from the Swiss Innovation Agency to explore his idea of creating a blanket of artificial snow on the Morteratsch glacier as a means of protecting it from further melt. The team is looking at using gravity feed of water from high altitude glacial lakes to minimize energy costs, but there is a lot of work to do. The hope is that their solution could extend beyond the lucrative ski/tourism industry to communities in developing nations, such as Tibet and India, that rely on glacier melt for crops.

CN Advertisement – circa 1950s

Will snowmaking be the way to slow global glacier melt due to climate change on a large scale? Absolutely not. But it is an interesting application of an accidental 1940s Canadian discovery – I mean, you knew there had to be Canadians involved from the beginning, eh?

Published by joanneomeara

Professor, Department of Physics, University of Guelph

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