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..