Settled Science: Snowflakes

 

Every winter day across the Northern Hemisphere millions of cross-country skiers rely on the settled science of snowflakes. The practical application involves the use of wax in order to “stride and glide” across the snow.

How does it work? You glide on the tips and tails of the skis, so you put on those spots a very hard wax, like paraffin, that makes little friction with the snow. When you put your foot down in order to stride forward, you need on the ski under your boot a more sticky wax that will grip the snow for traction.

The art and science of waxing means choosing the right wax for the existing snow conditions. Snow crystals have sharper points when cold and dry, and are more rounded when warm and damp. When snow is fresh, cold and dry, a harder wax will do the job. Snow that is older, warmer or damp, requires a softer, sticker wax for traction.

If you put on too soft a wax, you get a big clump of snow attached to your ski bottom, and you would do better with snowshoes. Norwegians have gotten quite expert at this and win a lot of Olympic medals racing cross-country, along with other Scandinavians and Russians.

Here in Quebec last century Cree natives were amazed to see a Norwegian flashing through the woods over the snow, and they gave him a nickname. Until recently you could still buy his waxes branded with his legendary name: “Jackrabbit Johannsen.” (In 1982, at the age of 107, Herman Smith-Johannsen (1875-1987) was inducted into the Canadian Sports Hall of Fame.)

Of course, when the snow gets deep and stays very cold as it does in the Arctic, it compacts into solid ice, part of the ebb and flow of Arctic Sea Ice extent. When the ice cover retreats, the air becomes moist from evaporation, snow falls and the ice grows. When extensive ice restricts open water, the dry air produces too little snow to replace ice melted by the sun, and the cycle begins again.

The science is described more fully in Arctic Sea Ice: Self-Oscillating System

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