What is the principle of sports running on snow?  

To begin, snow is a crystalline phenomenon in which water vapor in the atmosphere freezes and falls to the ground. At less than 0 degrees Celsius, the moment water vapor meets fine dust in the clouds, it sticks and makes snow crystals. There are about 10 water molecules in snow crystals. Therefore, the crystal shapes of the snow vary. Snow types are classified into about 80 types according to the crystal shape and about three types depending on the size of the snowflake. 

Snow quality is determined by the air content of the snow. There is a lot of empty space between the crystals, so when you step on the snow, you can feel it being soft and crunchy. The higher the air content, the softer the snow becomes, and the lower the snow quality, the harder it becomes. The snow suitable for skiing is powder snow with moderate air content and low moisture. This makes it possible to speed up because the blades of the ski/snowboard can easily press in the snow. Since the snow is fluffy, there is much less risk of injury even if you accidentally fall. Powder snow is usually made around minus 5 degrees Celsius.

Skis move due to friction, and when heat is generated between the snow-covered floor and the surface where the ski board touches, a thin film of waters forms, helping the ski board speed up.