Cold Weather Makes Snow Squeak: The Science Behind It

In summary, walking on snow creates a sound due to the friction of ice grains rubbing against each other. This sound is more noticeable at colder temperatures due to the water in the snow freezing and creating a dry, crunchy snow. At warmer temperatures, the snow is more compact and the sound is less noticeable. Ski wax formulations also vary based on temperature.
  • #1
AEM
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Right now it's a bit chilly in the upper midwest (-21 degrees this morning at 6:00 am; -23 degrees predicted for tonight). When walking our dog this afternoon, my wife and I noticed that the snow underfoot squeaked louder that usual. We observe that snow makes a qualitatively different sound depending on temperature with the most noticeable squeaking starting at about -10 degrees. (All degrees in this post are Farenheit.) Why should the sound made when walking on snow depend on temperature, and why should it appear louder the lower temperature?
 
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  • #2
Everything you ever wanted to know about snow
http://nsidc.colorado.edu/snow/faq.html

Why does snow crunch when you step on it?
At what temperature does it crunch?

A layer of snow is made up of ice grains with air in between the ice grains. Because the snow layer is mostly empty air space, when you step on a layer of snow you compress that layer a little or a lot, depending on how old the snow is. As the snow compresses, the ice grains rub against each other. This creates friction or resistance; the colder the temperature, the greater the friction between the grains of ice. The sudden squashing of the snow at lower temperatures produces the familiar creaking or crunching sound. At warmer temperatures, closer to melting, this friction is reduced to the point where the sliding of the grains against each other produces little or no noise. It's difficult to say at what temperature the snow starts to crunch, but the colder the snow, the louder the crunch.
 
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  • #3
AEM said:
Right now it's a bit chilly in the upper midwest (-21 degrees this morning at 6:00 am; -23 degrees predicted for tonight). When walking our dog this afternoon, my wife and I noticed that the snow underfoot squeaked louder that usual. We observe that snow makes a qualitatively different sound depending on temperature with the most noticeable squeaking starting at about -10 degrees. (All degrees in this post are Farenheit.) Why should the sound made when walking on snow depend on temperature, and why should it appear louder the lower temperature?
I suppose this site offers as good an explanation I can find:
http://cimss.ssec.wisc.edu/wxwise/squeak.html

Apparently, at the colder temps, the water in the snow freezes, and thus becomes a dry (i.e, water in its frozen state) snow, causing crushing of the ice crystals , and hence, more noise as you walk on it; also, the sound is not absorbed as well as a fresh fallen snow, so the sound is louder. I've noticed, however, that when the temperature is around 20 to 30 degrees or more, degrees F, the snow is relatively quiet when you walk on it; in the 0 to 20 degree range, degrees F, you get a "crunch,crunch" sound; and when the temperature drops below zero, you get that "squeak, squeak" sound. I'll check it out tomorrow morning when the temperature is expected to drop to 5 below in these parts. Interesting!
 
  • #4
Thanks for the feedback and links. My wife (who is an applied mathematician) and I had surmised the answer, but it's nice to have confirmation. Stay warm!
 
  • #5
Interesting links. I also know that different ski wax formulations are used for different temperatures- don't know any real details, other than they are different colors.
 

1. How does cold weather create the squeaking sound in snow?

The squeaking sound in snow is created by a phenomenon known as "cold weather acoustic emission." When temperatures drop below freezing, the snow crystals become cold and brittle, causing them to rub against each other and produce a squeaking sound.

2. Why does the squeaking sound only occur in cold weather?

The squeaking sound only occurs in cold weather because it requires a temperature below freezing for the snow crystals to become cold and brittle. In warmer temperatures, the snow crystals are softer and do not produce the same type of friction needed for the squeaking sound to occur.

3. Does the type of snow affect the squeaking sound?

Yes, the type of snow can affect the squeaking sound. Dry and powdery snow tends to produce a louder and higher-pitched squeak, while wet and compacted snow may not produce a sound at all. This is because the size and shape of the snow crystals can vary, affecting the level of friction and resulting sound.

4. Is there any scientific significance to the squeaking sound in snow?

While the squeaking sound in snow may seem like a fun and unique phenomenon, it also has scientific significance. Scientists use the squeaking sound as a way to measure the hardness of snow, which can provide valuable information for weather forecasting and avalanche prediction.

5. Can other materials produce a similar squeaking sound in cold weather?

Yes, other materials besides snow can produce a similar squeaking sound in cold weather. For example, some types of ice, such as lake ice or sea ice, can also produce a squeaking or cracking sound due to the same principle of cold weather acoustic emission. However, the squeaking sound in snow is unique due to the intricate structure of snow crystals.

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