Determination of snowmaking efficiency on a ski slope from observations and modelling of snowmaking events and seasonal snow accumulation

Abstract

Abstract. The production of Machine Made (MM) snow is now generalized in ski resorts and represents the most common method of adaptation for mitigating the impact of a lack of snow on skiing. Most investigations of correlations between snow conditions and the ski industry's economy focus on the production of MM snow though not one of these has taken into account the efficiency of the snowmaking process. The present study consists of observations of snow conditions (depth and mass) using a Differential GPS method and snow density coring, following snowmaking events and seasonal snow accumulation in Les Deux Alpes ski resort (French Alps). A detailed physically based snowpack model accounting for grooming and snowmaking was used to compute the seasonal evolution of the snowpack and compared to the observations. Our results show that approximately 30 % of the water mass can be recovered as MM snow within 10 m from the center of a MM snow pile after production and 50 % within 20 m. Observations and simulations on the ski slope were relatively consistent with 60 % (±10 %) of the water mass used for snowmaking within the limits of the ski slope. Losses due to thermodynamic effects were estimated in the current case example to be less than 10 % of the total water mass. These results suggest that even in ideal conditions for production a significant fraction of the water used for snowmaking can not be found as MM snow within the limits of the ski slope with most of the missing fraction of water. This is due to site dependent characteristics (e.g. meteorological conditions, topography).

Water Losses During Technical Snow Production: Results From Field Experiments

“…The two studies identified a huge range of potential water losses (0-59%). Moreover, the losses for air-water guns (snow lances) reported by Olefs et al (2010) and the results from Spandre et al (2017) strongly differ. Besides the temperature regression of Eisel et al (1988), correlations between mass loss and meteorological settings have not been investigated.…”

“…They concluded that only 25-50% of the water used for snow-making was finally recovered as snow on the ski runs. Recently, Spandre et al (2017) presented results of mass balance measurements collected during operational snowmaking in a French ski resort. During five snow-making sessions performed in November and December, 41-89% of the snow could be detected in a 20 m circle surrounding the peak of the accumulation.…”

“…During five snow-making sessions performed in November and December, 41-89% of the snow could be detected in a 20 m circle surrounding the peak of the accumulation. From the regression function of Eisel et al (1988), Spandre et al (2017) derived that losses attributed to sublimation and evaporation were smaller than 10%. They suggested that the remaining loss would be attributed to deposition of the snow outside of the target area.…”

“…The information available on water losses during snowmaking is only based on two field studies (Eisel et al, 1988;Spandre et al, 2017) mirroring a narrow band of atmospheric conditions during 16 tests. The two studies identified a huge range of potential water losses (0-59%).…”

Air and wet bulb temperature lapse rates and their impact on snowmaking in a Pyrenean ski resort

“…In low elevation ski areas, snow making represents a key technology to buffer the impact of interannual variability of snow conditions, and is increasingly considered to be the most reliable adaptation measure for alpine ski resorts facing the consequences of climate change (Uhlmann et al, 2009;Spandre et al, 2017). However, for successful and efficient production of machine-made snow, particular air temperature and humidity conditions need to be met, generally defined by a wet bulb temperature (Twb) threshold.…”