Have you ever wondered why snow sometimes squeaks underfoot?
When you step on snow, you put pressure on it. Pressure causes heat. At temperatures above 14 degrees Fahrenheit, the pressure from your boot heats up the snow below it and melts it. This causes the snow to “flow” on a minuscule amount of liquid, making a relatively quiet sound. According to the University of Wisconsin-Madison website WxWise, this is how ice skates work. The pressure from the skates melts some of the ice, and the skater slides along the liquid.
But if the air temperature is below 14 degrees Fahrenheit, the pressure from your step does not create enough heat to melt the snow, and the ice crystals rub against each other, making a squeaking sound.
Here is the sound of my shoes sliding and crunching on packed snow when the temperature outside was 13 degrees Fahrenheit: