Artificial snow is now a common sight in the Alps
If too little snow falls in ski regions, operators in many places turn to technical equipment. Snow cannons and snow lances atomise water into fine droplets and, using an air stream, they blow them onto the ski slope where they settle as artificial snow. A few decades ago, the technology was only used for the purpose of supplementary, corrective snowmaking – in low areas with little snow or to prepare slopes for sports competitions. Over the years, what was once used as a corrective measure has since become the norm: Throughout the Alpine region, snow operators rely on artificial snow to make sure the ski season lasts long enough.
During a year, a ski resort first becomes profitable after around 100 days of seasonal operation – which is a challenge in lower areas especially. In Austria, artificial snow is therefore now used on 70% of the Alpine ski slopes, and in Italy this figure is 87%. Aside from the Alps, operators rely on artificial snow in German ski regions such as Eifel, Sauerland and the Black Forest. The altitude at which sufficient natural snow falls for ski operations throughout the entire season is becoming higher due to climate change. There will be an increased need for artificial snow systems in order to continue attracting ski tourists. At the same time, the environmental impacts of artificial snowmaking are discussed with increasing controversy.
High environmental impacts and costs as a result of artificial snowmaking
Artificial snowmaking for 1 hectare requires 3 million litres of water per season. To enable the punctual supply of such large amounts of water, a special infrastructure is required including pumping stations and storage reservoirs. In Austria alone there are 450 of these artificial lakes. With the high water requirement also comes the risk of supply bottlenecks in the surrounding municipalities. Furthermore, the production of artificial snow is an energy-intensive process. The relatively warm water extracted from the storage lakes has to be cooled down before it can be fed into the snow cannons. These in turn need to be heated electrically so they don't freeze.
The energy required for these and other factors equates to 15,000 kWh per hectare, per season. Operators now use snow cannons throughout the day, which means they are unable to benefit from the cheaper rates at night. Artificial snowmaking is therefore extremely costly. One cubic metre of artificial snow costs the operator approx. EUR 3 to 5. Besides the high levels of energy and water consumption, snow cannons cause other environment impacts. For example, the noise pollution disturbs wild animals during their hibernation period.
The use of artificial snow is nowadays more or less inevitable. Nevertheless, it should only be used where it is absolutely essential. In some snow areas, snow cooling therefore provides a complementary solution.
Cooling coils delay the thawing of the snow
A snow cooling system consists of a snow cooling unit and cooling coils which are anchored in the ground. A refrigerant (e.g. glycol) is fed through the cooling coils and cools the snow by means of the coils. This enables the snow to be maintained for longer and considerably reduces the need for snowmaking on the cooled area. Snow cooling is suitable for natural and artificial snow and can also been installed on slopes. While the cooling coils can remain in the ground until the end of the season, the cooling unit can be conveniently moved around and cool several pipe systems as required. An adapter on the cooling unit makes it easy to transport on the mountain with a snow groomer. Apart from the power supply, no infrastructure needs to be prepared in order to operate the cooling unit.
Snow cooling especially makes sense for small areas
Snow cooling is ideal for particularly sensitive areas with limited space. For instance, a cooling system can significantly delay the thawing of snow in areas where there is a lot of direct sunlight. Even when the weather is not ideal, stable competition conditions can be created at sport arenas or on half pipes thanks to snow cooling systems. Cooling can be used on the in-run and the landing area of ski jumps. When used in ski lift areas, it prevents the snow surface from turning to slush despite the large number of people who pass through. Snow cooling can also ensure a stable snow surface around children's lifts in low areas, at hotels and in demonstration areas for skiing courses.
Good navigability thanks to intelligently distributed cooling performance
For safe and convenient navigability, the cooling of snow surfaces must be carried out professionally. On the one hand, the cooling performance must be sufficient to create the same snow properties and prevent the formation of waves at all distances from the cooling coils. On the other hand, the snow must not be cooled to the point that it freezes over. On behalf of FrigorTec, the Federal Institute for Snow and Avalanche Research identified relevant factors that are important for good navigability, and on the basis of which snow cooling can be optimised (e.g. the distance of the cooling coils and the temperature of the coolant).
Operators can use a snow cooling unit to selectively reduce the snowmaking requirements at their facility and to ensure consistently good navigability. This enables them to save water and energy costs and to reduce their environmental impact to the necessary minimum. The actual energy savings also depend on other factors including ambient temperature, direct sunlight and rainfall at the site.