Having our first real snow of the year reminded me of something I heard as a kid: when you walk on snow you can gauge the temperature by the pitch of the ‘squeak’ or ‘crunch’ it makes. So of course I decided to do some fact finding, or at least search the web. I found an interesting summary from this blog: http://blog.sciencegeekgirl.com/2008/12/29/why-does-snow-crunch-under-your-feet/ as well as a link to the National Snow and Ice Data Center:http://nsidc.org/snow/faq.html
Apparently at about –10°C there is a change in sound from ‘Crunch’ to a ‘Squeak.’ They suggest there is a thin layer of water on the crystals lubricates above –10°C and does not below –10°C , the squeak sound comes from the crushing of the ice crystals.
I was unable to find anything that indicated the pitch of the squeak changes. On a different note, I noticed last time we visited the beach that my bare feet on the sand causes a similar type of sound.
In any case, next time you go for a walk in the show, listen..