I don't know if you saw my MaxBotix snow depth ultrasonic rangefinder.
Here is the thread:
http://www.wxforum.net/index.php?topic=24547.msg235695#msg235695I have the outdoor packaged unit with the self-cleaning feature. I have the serial data fed into my Linux box (mini-ITX), but there is no reason that a Pi couldn't do the job. (I was considering it, but I had it working pretty well on the Linux box and decided not to migrate it to the Pi)
This article on MaxBotix might be of interest:
http://maxbotix.com/articles/074.htmGreg H.