From Natural to Artificial Snow under Climate Change - ecological, hydrological and socio-economic assessment
Convener: C. de Jong  | Co-Conveners: Breiling , Dr. Sokratov 
Oral Programme
 / Fri, 24 Apr, 11:45–13:15  / Room 20
Poster Programme
 / Attendance Fri, 24 Apr, 13:30–15:00  / Halls X/Y
Artificial snow is increasingly being applied on ski slopes in the Alps and other mountain regions worldwide as the spatial and temporal distribution of natural snow is becoming decreasingly reliable under climate change. Artificial snow consists of ice crystals that are usually manufactured at maximum temperatures of -3°C from water. Water is expelled under high pressure into the air, where it freezes to form ice crystals. Artificial snow does not have the same physical properties as snow. The ice crystals are spherical which results in a snow density that is on average four times higher than natural snow and a surface that is up to 60 times harder. The thermal properties also differ, leading to warmer soil temperatures under a deep artificial snow pack and enhanced soil freezing under compacted natural snow. Alpine vegetation has been shown to respond to snow-related changes in soil temperature, disturbance, timing of snowmelt and ion input. In order to manufacture 30 cm of snow cover over one hectare of snow surface, approximately 3700 m3 of water are required. This is more than the water requirement for agricultural irrigation. For the production of artificial snow (30 cm over one ha) the average energy requirements are 25000 kWh and the average investment costs are estimated at least at 110 000 Euros with average running costs of 6000 Euros. According to the CIPRA these costs are higher, especially when related to lower altitude ski areas. The price difference for snow-making has to be considered with relation to every 100 m difference in altitude. The classical arguments for the expansion of artificial snow are the necessity of winter tourism to maintain the local and regional economy. On the other hand, the high investment costs have to be weighed against the amortization of the equipment. It takes on average 15-20 years to amortize the artificial snow infrastructure, taking into account on average 100 snowmaking days, i.e. days with subzero temperatures, per season. However, in many low altitude regions or temperate zones less subzero days are available. If climate change with its clear trend of increasing temperatures in the mountains continues, less and less reliable snowmaking days will be available and some regions may gradually turn into unprofitable zones depending on wind (e.g. foehn conditions), evaporation, aspect and altitude. Under global warming, lower altitude resorts that benefit from the proximity to large cities are the first to be threatened since artificial snow cannot be produced under these conditions. Furthermore, the use of renewable energy sources needs to be considered for the expansion of artificial snow production and the maintenance of ski pistes. Even though water conflicts are emerging in mountain communes located downstream of snow making facilities, few data are available on water consumption for the tourism industry. Improved water monitoring and cryosphere management are important considerations for the future. Contributions are welcome from scientists as well as practitioners such as lift operators, tourism managers, financers and local stakeholders.