About our project
As part of our project work, we would like to find out how much energy is needed in ski resorts for artificial snow. In addition, we compared and studied artificial snow with natural snow.
Every year, many snow sports enthusiasts spend their free days on skis or snowboard. Due to climate change, we are more and more dependent on artificial snow. Today alone, according to Statista (statista.com), Switzerland has about 54% artificial snow, Italy about 90% and Austria about 70%.
In April 2023 we had the pleasure of interviewing Fabian Wolfsperger (wsl.ch) from the WSL Institute (Institute for snow and avalanche research, wsl.ch) and asked him our questions in a zoom call. Fortunately, we were able to find great answers to all our questions and are happy to share our results with you below.
Decrease in snowfall
In the recent years, we’ve seen a significant downward trend in snowfall. Below 1,200 meters, there’s been a drop of about 20-30%. At elevations above 1,700 meters, there’s even been a drop of up to 50%. That’s a significant trend that’s been developing over the last 30 years. An example of this is Klosters, where the average snow depth decreased from 67 cm to 44 cm. In Sedrun, the snow depth decreased from 51 cm to 36 cm, which corresponds to a decrease of 30%, at an altitude of 1,400 metres above sea level.
Last winter was the lowest on record, and low rainfall contributed to this phenomenon. In the future, much precipitation is expected to occur in the form of rain instead of snow.
Differences in the structure of snow
Now to the differences between natural and artificial snow crystals. Natural snow is created by growing on a solid particle (sublimation germ). In doing so, it forms a filigree construct that is always very thin in one dimension. Artificial snow, on the other hand, is created by freezing water droplets from the outside to the inside and forming a small globe of ice.
Snow on the ski slopes
Preparing the slopes requires a lot of work, especially in the case of fresh snow. In the beginning there is a big difference between natural and artificial snow crystals, but over time the natural snow is also reprocessed and resembles artificial snow. This reduces the amount of work involved. The density of the snow is about 400 kg/m³. It is not clear that artificial snow is more dangerous than natural snow. The Advisory Centre for Accident Prevention (BFU, bfu.ch) does not yet have any clear findings on this. Accidents on the slopes do not increase linearly with the number of people, but there are several factors that play a role.
Costs and weather requirements
The cost of producing snow is estimated at around CHF 5 per cubic metre. A kilometre of slope costs around CHF 1 million, including infrastructure, and an additional CHF 30,000 in operating costs. The ability to produce snow depends on the temperature and humidity. The cold air is used so that the snow can also be produced by evaporation. The nucleation temperature for snow crystals is usually between -2 and -4 degrees Celsius, depending on the water.
Effects of global warming
Global warming theoretically has an impact on snowfall. New snow can be reduced by up to 90%, while spring snowfall can be reduced by about 50%. This has an impact on water resources, energy production and other areas. Experiments have already been carried out on the Morteratsch glacier. Winter sports, and skiing in particular, have an impact on the soil and plants in Alpine regions. Although these effects are not as negative as compared to hazardous substances, there are still challenges to be overcome. Artificial snowmaking creates extra water, which in turn affects plants that prefer drought. Winter sports also interfere with the natural ecosystem and can affect biodiversity. The snowpack isolates the soil and influences the growth of plants. For example, sections of the slope above the ridge can lead to the displacement of rare plant species.
The earthwork required for the construction of ski slopes can also cause lasting damage to the plants. This is because the growing season in alpine regions is very short, and it can take years for the plants to recover. Therefore, it is important to use the right seeds and the necessary know-how in planning work to minimise damage.
How can winter sports be made more sustainable?
The question arises as to whether winter sports can be made more sustainable. Energy and water are key issues here. The more sustainable the energy supply, the better for the environment. It would be sensible to make energy available locally, for example by using hydroelectric power stations in storage lakes and photovoltaic systems. Efficient snow production is also important by producing only as much snow as necessary. Here it is important to know how much snow is available and how much is needed for snow production. A snow management system can help to optimise production.
Water is another key issue for winter sports. In Switzerland, water is generally available, but it must also be available for agriculture in dry times. By storing water in reservoirs and making snow, water can be kept on the mountain. In November and December, water is usually not scarce and comes back on its own. Over the next 30 years, the expansion of reservoirs will play a dominant role in this issue, as they will have a greater impact.
However, water availability is a limitation for snowmaking, especially in countries such as China, Japan and Germany. Nevertheless, there are opportunities to make winter sports more sustainable by using energy and water efficiently and by minimising damage to soil and plants.
We had the intention to make the understanding of this huge text easier by means of a video. Some of this footage was created by ourselves. We limited the text to the most necessary and then used an AI voice as a reporter. Overall, this was also an exciting part, because it has to do with creativity.
Experience and reflection
While thinking back on our work for the project, we came to the decision that we already knew a few things about the subject at the beginning, for example, that artificial snow is very expensive and that it will be used more and more as time goes on. What we were not aware of, however, was the impact that artificial snow has on the environment. For example, a meadow is strongly changed by the artificial snow, because much more water melts towards the end of the winter and thus displaces plants that rather prefer the dryness.
Now we would like to thank Fabian Wolfsperger from the WSL Institute in Davos for his commitment and the valuable information he gave us. Thanks to him, we were able to carry out our project work. We really enjoyed the cooperation with Fabian and within our project team and we are very satisfied with the outcome.
Sedric, Philipp and Janik
Reviewers: parents of all the team members
We obtained all essential information and data from our interview and additionally used the SLF and WLF websites to further inform ourselves. In addition, we studied Technoalpin’s website to get a better understanding of how the snow gun works.