Snow of the future

Artificial snow nowadays is as much a part of skiing as is traditional après-ski. In Mayrhofen, satellites and big data are now helping to ensure the optimal use of this white gold. Furthermore, inventive Tiroleans are working on how to make technical snow production more efficient and energy-saving.

"Lapis philosophorum" is the name the ancients gave to it, the philosopher's stone, a substance, which was supposed to help realise a long-cherished dream of humans – turn base metal into precious metal. Alchemists experimented for centuries, without any success, they just couldn't create gold. Canadian researchers working with Raymond T. Ringer were more successful, they – without intending to – produced white gold. In the 1940s they sprayed water into a wind tunnel to examine jet engine icing at low temperatures – and turned water into snow.

Nowadays, it is no longer possible to imagine alpine ski pistes without this white gold or snow cannons and snow lances, which produce artificial snow. Since 2000, about 1.3 million euros have been invested in artificial snow in Austria, 154 million for this year's season, 62 alone in Tirol. More than 80 per cent of the 7300 hectares of skiing area in Tirol can be artificially snowed. The costs run into millions, at Ischgl ski resort they pass the ten million mark every season.

A cost factor that shocks him every time he looks at the annual balance sheet, Michael Rothleitner, chairman of Mayrhofner Bergbahnen, admits openly. Since 2009, he has been the head of 42 transportation facilities, just under 140 kilometres of pistes, three impounding reservoirs, 35 snow groomers and 338 snow generators, the not so military name for snow cannons and lances. Not only a look at the balance sheets, but also a second look at the pistes has given him food for thought.

At the beginning of the season, snow groomers would often sink deep into the low layer of snow with their sign – this led to dirty snow full of brown particles of soil, which on the one hand is not attractive and on the other hand absorbs sunlight and melts more quickly. However, when the season was over there was still snow on the piste, which – to make it to melt more quickly – would be pushed aside by snow groomers and "at times had to even be removed with grey lime," Rothleitner explains. He, therefore, had three reasons to take a closer look at snow generation and the depth of snow produced. They found the right partner in PowerGIS. This company from Salzburg uses the GNSS technologies GPS and GLONASS to measure snow depth. The snow groomer sends its current altitude via GPS, this is then compared with a digital – snow-free – model of the terrain under it, the difference is the actual snow depth. It is measured in real-time, the results are sent directly to the control centre and other snow groomers. "In the first winter we equipped

a few snow groomers with the system in order to find out how deep we could pierce the snow with the signs or where artificial snow was not necessary," the manager of the ski resort in the Ziller valley remembers. They saw exciting opportunities and decided to equip their entire fleet of groomers with the system, the first ski resort in Austria to do so. The investment costs of half a million euros per snow groomer stimulated another debate, "What else can we do with the data we have collected?"

A process, which answered questions and at the same time gave rise to many more. "As we do not know when it is going to snow or how much, ski resorts tend to neglect the natural snow," Rothleitner says. Artificial snow, which initially was only used to patch up snowless piste sections, now forms the basis of the snow cover. Artificial snow costs about three to five euros per cubic metre. One cubic metre of water, as a rule of thumb, can generate 2.3 cubic metres of snow. A rule of thumb, which the qualified lawyer wanted to investigate further, i.e. wanted to re-measure. "We were horrified when we saw the results." Understandably, there were sections where the output on the piste came to just about 0.69 cubic metres of snow. And the rest? "Water gets blown away before it falls to the ground in a frozen state. It evaporates. It lands as water on the piste and trickles away," he says, mentioning a few reasons. But how much water is lost where – and therefore energy and money – is a question, which the head of Mayrhofner Bergbahn admits cannot be answered so easily and in no way on its own.

As a consequence, they established the "Competence Centre for Snow Management" together with PowerGIS and Wissensberater MDS in 2012 in order to exchange information with other ski resorts, ropeway companies and manufacturers of snow cannons. "The ball eventually started rolling," Rothleitner remembers. The terrain data and measured data became more precise, they created a measurement series of snow covers taken over several seasons. The results were sobering. "We found that we got natural snow from the end of January, which we actually need, but we would produce so much snow up to the end of January as though there was no tomorrow. We, therefore, wondered how much we could reduce snow production by up to the end of January and still get by until the season ended."

The solution brought big data to Mayrhofen. The University of Applied Sciences Kufstein, IBM and for the moment BI plus GmbH joined forces with IT specialists to enter weather data – wind, temperature, snowfall, solar radiation… – into the system and combine it with terrain data and snow production data. "We now have 6.5 billion data points in the system," Rothleitner reports with pride. The flood of data was used to de-

velop a model that would enable them to get closer and closer to the optimal saving from year to year. "Two years ago I said that we could save about 35 per cent of the costs for producing snow. Today I say 50 per cent because technology is also changing."

Water consumption itself has been reduced by a quarter in specific piste sections in the last three years. He expects to also be able to make significant savings on the diesel – 25 litres per operating hour - consumed by a snow groomer. Big data also enables something else, the masters of snow at Mayrhofner let it snow on the computer. "Our model lets us make simulation games, make virtual decisions and then we see what happens." He believes that there will be a model in three years' time, which will be able to guarantee snow and be energy-efficient and cost-efficient, too. But what if you back the wrong horse, if the weather plays a trick on the calculation model? Mayrhofner Bergbahnen has two – possible – solutions in test mode on the piste, an innovation from the Tirolean uplands and research output from a university of applied sciences in Innsbruck.

Frank Wille, a fully-qualified motor mechanic from Pfunds, is an expert for special technical solutions. One such solution came after his workshop received a query in 2009, namely a propeller snow generator with a cooling unit. Being a newcomer to snow, Wille did not know much about snow cannons and, therefore, approached the subject "with an open mind". One solution had been "extremely large and non-transportable", a second one went completely the other way – a supersonic nozzle. He worked out a solution, used a test nozzle to determine that he was on the right track, made more accurate calculations, built a prototype. The measured values already looked promising with the third prototype, his supersonic snow nozzle produced snow at temperatures at which conventional snow generators were not able to work as an "artificial" Mother Hulda.

A lack of money forced him to halt the project. But then in autumn 2014 the Mechatronics Cluster Tirol at Standortagentur Tirol invited him to a snow symposium. There he met Michael Rothleitner who was interested in the supersonic snow nozzle. Wille packed it into his car boot and drove to Mayrhofen – he made it snow at +2.7°C and 72 per cent humidity. Mayrhofner Bergbahnen then called in the Swiss Institute for Snow and Avalanche Research who were immediately interested. The experts tested the new product in Mayrhofen and then, according to Wille, "it just took off." The snow researchers got Bächler, the artificial snow specialist from Switzerland, on board who they met – late in the evening, rainy grey weather, in the only restaurant open in the off-season on Arlberg

mountain – Wille and Rothleitner too, to sign a confidentiality agreement. Wille then concluded a licence agreement, ten demonstration models were built. Two are now being tested in Mayrhofen, others in Sweden and Switzerland.

"The snow nozzle has enormous potential at limit temperatures," Rothleitner also believes in the innovation but because of the high energy costs it cannot be used at present to constantly produce artificial snow. But it could be used in autumn for the beginning of the season and in spring, at warm temperatures, to patch the snow cover optimally. NIVOSUS can also make it snow when it is warm. Thomas Obholzer and Ronald Stärz are working not on a new snow generator but on energy-saving add-on technology.

"For snow cannons to even be able to generate artificial snow, you need so-called nucleating substances," Stärz explains, who just like Obholzer is also a researcher at the Management Center Innsbruck. Substances, which have nothing to do with atomic energy, but instead are solid particles that enable drops of water to crystallise. Water and compressed air are pressed out of the nucleator nozzles on the snow generator, the mixture cools in the air and small solid ice particles are formed. A second nozzle sprays water, when these drops of water hit an ice particle, the freezing process starts and the drops of water turn into artificial snow falling to the ground. Prerequisite: temperatures of at least -3°C. If it is warmer, wet slush lands on the ground and then freezes there.

Obholzer and Stärz do not need ice particles. They produce an electric field where they can simulate a natural ionosphere. "We can give drops of water information, as it were, that they are in fact already ice crystals," Stärz explains. Therefore saving energy input for the nucleator nozzle. Obholzer, "A normal snow cannon needs 20 kilowatts, four of them for the compressor for the nucleator nozzles, then another 1.5 to two to heat them. Our system only needs a few hundred watts." But that's not all. The first tests conducted in Mayrhofen show that the snow lance with added MCI technology produces dry snow six centimetres high at an ambient temperature of +1,5°C, but without NIVOSUS only three centimetres of slush. Obholzer and Stärz are currently testing their system with a snow cannon. There are already interested parties in the patented NIVOSUS system, also because it has one more advantage over conventional snow generators. "The snow crystals," Obholzer explains, "grow small branches, so the snow produced has a slightly higher volume. Snow output, therefore, increases with the same amount of water."

Another Tirolean snow maker has higher efficiency in mind. Michael Bacher attracted

international attention in autumn 2014. In Obergurgl he ventured the step from research lab to nature, his "snow cloud" commenced operations. At minus temperatures (Bacher, "-10 to -20°C is ideal.") drops of water are sprayed into the cloud chamber. The droplets cool down to below freezing because of the low ambient temperature but they do not freeze – a cloud is formed. Small ice particles are added to this cloud as nucleating substances, which act like magnets to continually attract water molecules and bind them to them. The results are – compared with the frozen drops of water from snow cannons and lances – snow crystals, which fall from the cloud chamber to the ground in the form of powder snow.

"The first year has shown that our system works," Bacher states. And in fact so well that this and next winter he will be working with an adapted cloud, "Our cloud chamber was too small." Even though he was able to produce snow with high humidity and at minus two degrees, it works best at lower temperatures – from one cubic metre of water he can make 15 cubic metres of snow, significantly reducing the amount of energy used. Bacher admits that they still haven't worked out how to get the snow on the piste. "At the moment it is being shoved to the sides and then taken away. But it is not exactly the ideal solution." Using the generated data, he wants to develop his cloud so that it will be able to recognise external conditions – temperature and humidity – and can then mix the best air-water-ice particle ratio itself. Should it work as hoped, he plans on launching his invention in 2017. His first goal will be pistes with small areas, which will provide the best skiing and riding experience on close-to-natural snow. His long-term goal is to make mobile platforms that produce Bacher's snow and transport it themselves to the pistes.

Still a long way off, but it could also benefit Michael Rothleitner. The boss of Mayrhofner Bergbahnen estimates that "at the end of the day we will be able to save 50 per cent of the resources." An important step, he says, as in times of climate change ski resorts are scrutinised in the media, "people discuss who is behaving in an environmentally friendly way and who isn't." It is, therefore, necessary to communicate openly about how much and why as well as how efficiently and respectfully energy, electricity and water are being used. "The green footprint of the mountain experience is going to be a key issue," Rothleitner is convinced, as well as positive, that he will be able to convey to visitors that they are acting in an ecologically responsible way – even without finding the famous philosopher's stone.

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