According this this site, http://www.weatherunderground.com/snow/snowhelp.asp
, the snotel sites don't measure snowfall. They measure snow depth. Is that true?
If so, then measuring a storm total by comparing starting depth and ending depth is not the same method the ski areas use. Colorado ski areas clear the measuring base every 24 hrs which eliminates the effect of new snow weight compressing the older snow underneath.
Depending on how often you clear the snow, the higher the total will be. I've experimented with clearing every 12 hours and I've seen storm totals increase by as much as 20% depending on how dry the snowfall is. I've wanted to clear every hour and see what that does but haven't been able to yet.