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Why does snow squeak underfoot?

Posted at 4:20 PM on January 5, 2010 by Paul Huttner

You can hear your neighbors coming a mile off these days.

As the temperature plunges, the once quieting snow starts to "squeak" underfoot. Why is that?

It turns out that there are two answers. Pressure and temperature.

When your foot comes down on the snow, your body weight exerts additional pressure on the snow crystals underfoot. When it's "warmer" out in winter, the extra pressure actually causes some of the snow to melt underfoot. This causes a lubricating effect and the snow crystals slide quietly by each other as they are compacted beneath your foot.

But something different happens when the snow temperature is below about 14 degrees Fahrenheit. The pressure applied is not great enough to cause melting, and the snow crystals break and crash into each other as you step on them. The resulting sound is the squeaking you hear on cold winter days and nights.

That's why you hear squeaky snow only when it's cold outside.

It appears more snow and more squeaking are on the way courtesy of tomorrow's Alberta Clipper and subsequent slap of arctic air. You may be squeaking away until the moderating trend begins in earnest on Sunday.

PH

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