Of the medals awarded at the 2022 Winter Olympics in Beijing, 24% were for events involving cross-country skiing, the biathlon and Nordic combined. Although much research has focused on physiological and biomechanical characteristics that determine success in these sports, considerably less is yet known about the resistive forces. Here, we specifically describe what is presently known about ski-snow friction, one of the major resistive forces. Today, elite ski races take place on natural and/or machine-made snow. Prior to each race, several pairs of skis with different grinding and waxing of the base are tested against one another with respect to key parameters, such as how rapidly and for how long the ski glides, which is dependent on ski-snow friction. This friction arises from a combination of factors, including compaction, plowing, adhesion, viscous drag, and water bridging, as well as contaminants and dirt on the surface of and within the snow. In this context the stiffness of the ski, shape of its camber, and material composition and topography of the base exert a major influence. An understanding of the interactions between these factors, in combination with information concerning the temperature and humidity of both the air and snow, as well as the nature of the snow, provides a basis for designing specific strategies to minimize ski-snow friction. In conclusion, although performance on “narrow skis” has improved considerably in recent decades, future insights into how best to reduce ski-snow friction offer great promise for even further advances.

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Snow as a construction material has been used for centuries, with igloos among the first examples. Each winter, snow and ice villages, buildings, and artwork are built in many places around the world. Machine-made snow manufactured by snow guns is commonly used for constructions made of snow. However, only a few basic studies on machine-made snow have been published. Knowledge based on experience and studies on natural snow constitute the basis for constructions made using snow and ice. Through material tests on machine-made snow used for construction, data on important physical and mechanical properties have been established that aim to improve and optimize safe constructions made from snow. Strength tests have been performed using two different qualities of machine-made snow. Specimens used for testing were cut out from one block of snow that had a coarse-grained structure with clusters of ice in the snow and from one block of snow with a fine-grained and homogeneous structure. The density for each tested snow sample was measured and strength tests were performed at different deformation rates to investigate the relationship between mechanical properties and deformation rate or strain rate. The load response curves achieved from the strength tests were used to evaluate compressive strength, Young's modulus, and the residual modulus. The results show that compressive strength increases with increasing density. Increasing compressive strength with an increasing strain rate was also observed for fine-grained snow quality specimens, whereas no similar tendency was observed for coarse-grained snow. The residual modulus increased with an increasing strain rate up to a certain critical value for the fine-grained machine-made snow specimens. Regression analysis was used to investigate whether any dependence was observed between the calculated mechanical properties; no further relationship between the mechanical and the physical properties was noticed.

A B S T R A C TThe arrival of natural snow is often delayed nowadays due to global warming. This causes problems for ski resorts and other places where winter activities in different forms take place. Storing snow provides one solution for the winter business industry to deal with this problem. However, there is so far very little research concerning this question. In this paper a review of current knowledge of snow storage and experiences from mainly Scandinavian snow storages is presented. New results concerning melting losses of stored snow from a trial experiment in the north of Sweden are presented. These results are compared to theoretical calculations. The model used for the calculations is shown to be useful for estimating melting losses of insulated piles of snow. Thus the calculations can serve as an important background when designing an insulated snow depot. The model can also be used to compare different insulating materials and to determine properties such as thickness of the insulating layer needed to sufficiently insulate the snow. By minimizing the surface area of insulated snow depots, melt rate due to heat from the air, sun and sky, which constitute the largest part of the total melt, can be reduced. The quality of insulating materials used will be subject to annual observation. Commonly used insulating materials such as bark, wood chips, cutter shavings and sawdust deteriorate.