Snowmaking – how much water does it consume?

The literature defines 12 types of natural snow and only one artificial snow, indicating that it is in granular form, of considerable density, and has a pressure resistance three to five times greater than natural snow. It is also characterized by high humidity, usually over 35%, while the humidity of snow falling in the Alps is usually around 15%.

Despite the fact that we have 12 types of natural snow and you will never find two identical flakes, artificial snow is currently the most anticipated type of snow for all those who practice white madness on the ski slopes.

What we use to make snow on ski slopes is commonly referred to as “artificial snow.” However, the correct term for the product of snow cannons is “technical snow.” It consists only of water and air and in this respect does not differ from natural snow. What makes it different are the conditions of its formation. While natural snow falls when it wants, and even in May… It is technical snow – artificial snow that requires strictly defined conditions of formation.

For it to be created and its production to be effective, the air temperature must fall to at least -2^oC, and ideally it should drop to -8^oC. Air humidity should be as low as possible, and the temperature of the water used for snowmaking must reach an optimal temperature of 0.5^oC. The pressure of the water supplied to the snow cannons is also important, with the higher the pressure, the more efficient the snow-making process. All of these elements are analyzed in detail and checked by professionals working at the ski resorts. Precise information on temperature and humidity determine whether the hundreds of thousands of zlotys that have been invested in snow production will not flow down the slope with the first thaw. Industry publications have indicated that 1^{m3 of} snow costs between 3.5 and 5 euros.

Efforts to make the ski and commercial season last as long as possible are understandable. Snow produced by cannons stays on the slopes up to four times longer than natural snow. This is due to the fact that it has a much lower air content than the real thing. Natural down of 1^m3 weighs approx. 400 kg, and the weight of the same amount of artificial snow is up to twice as much. Colloquially, we would say “more water in the water.” Thanks to its extremely compact form, technical snow melts slower than its natural counterpart and will return to rivers and streams much later than it does in the form of meltwater.

The CEOs of ski resorts, who count profits or losses at the end of the season, know a lot about the complexity of technical snow conditions and the uncertainty of its durability.

The construction of an entire snowmaking system and the daily analysis of weather conditions will be irrelevant in the absence of sufficient water availability. Therefore, the construction of a snowmaking system should begin with the construction of a water intake or storage tank of a size adequate to the area of the ski slopes.

Literature and trade journals indicate that a snow cannon, using 1^{m3 of} water, produces 2.5^{m3 of} snow. Of course, depending on the model, the equipment needs different amounts of water per second. According to statistics, for the formation of a snow cover of approx. 30 cm on a one-hectare slope requires approx. 1000^{m3 of} water.

Let’s take a look at a few stations in Poland. The description of the popular facility in Podhale states that the area of the resort is 42 hectares. The large ski station in the Silesian Beskid has an area of 8 hectares. So is another, in the Karpacz area. Each of them will use the water necessary for snowmaking to ensure the comfort and safety of skiers, providing them with the right conditions on the slopes. That is, 8,000^{m3 of} water will be used to snowmake the example 8 hectares with a snow layer 30 cm thick – a volume comparable to that needed to fill an Olympic swimming pool more than 2.5 times.

The total amount of water used for snowmaking can therefore be very large. Especially since the process of covering the slopes with snow is usually not a one-time thing, and in order to maintain proper conditions it will be repeated many times during the season.

Interesting fact: According to professional journals, the most efficient network of snowmaking equipment in Europe is located in Sölden[1]. The 11 snow cannons operating there are capable of producing 1.8^{m3 of} artificial snow per second, or nearly 6,500^m3 per hour.

It is mainly the availability of water that determines the ability to make snow on the slopes, and therefore the length of the ski season. For the purposes of snowmaking, the construction of water storage reservoirs should be beneficial, if not indispensable. The need to preserve the inviolable flow in mountain streams and the scarcity of water during winter periods should impose an obligation to build reservoirs for water storage and, at the same time, forbid the taking of water directly from streams in violation of the biological flow in a robbery and unreflective manner.

The problem of using water for snowmaking should be solved comprehensively, in accordance with the principles of rational use of water resources and in a way that does not burden the environment. Water stored in the artificial snowpack will return to circulation more slowly, minimizing large surges in streams due to sudden snowmelt. Artificial snow, with its more compact structure, melts more slowly and gives vegetation more effective protection from skiers.

What about artificial snow additives? According to the German Ski Association, chemicals are only used on trails intended for competition and only to ensure that all athletes have as equal downhill conditions as possible. In other circumstances, no chemicals are necessary in the production of artificial snow.

Let’s summarize, the issue of snowmaking on ski slopes is definitely more complex than it seems to the average skier. Temperature, atmospheric humidity, the availability of the necessary amount of water at a certain time, the conditions for the preservation of the inviolable flow in mountain streams or the construction of the necessary infrastructure require detailed analyses taking into account the natural, but also economic conditions.

A skier who uses the trails an average of 10 times a year would not want to worry about the quantity and quality of snow and should be assured that the artificial snow is produced in harmony and with respect for natural aspects, and his only concern should be the length of the queues to the ski lift.

[1] www.snowtrex.pl (accessed 02.01.2023)