Boundary Conditions for Artificial Snow Production in the Austrian Alps

To assess how meteorological conditions favorable for the production of artificial snow vary in time and space, wet-bulb temperatures are calculated using temperature and humidity data of 14 Austrian stations between October and April for 1948-2007 (station altitudes 585-3105 m MSL). Technical specifications of snow guns are used to define a wet-bulb temperature threshold value of -2 degrees C for snowmaking and a relationship between wet-bulb temperature and snowmaking capacity. The Mann-Kendall nonparametric-trend test is used to detect monotonic long-term changes in air temperature, relative humidity, wet-bulb temperature, and number of snowmaking days. It is applied multiple times to overlapping time periods to capture significant trends on different time scales. Results show a marked, common air-and wet-bulb seasonal mean (October-April) temperature increase between +1.5 degrees and +3.1 degrees C from 1980 to 1990 for a majority of stations with no trends thereafter. The number of snowmaking days per season decreased by 220 to 234 for half of the stations in the period around 1979-2003. No altitudes were especially affected by changes in the analyzed variables. The estimated volume of produced artificial snow shows high interannual variability and exhibits no trends at an hourly resolution over the last two decades.