First of all, the obvious - this icon indicates if the geocache can be found easily even if there is snow on the ground. If you live in a climate where you have snowy winters (like here in NY), a geocache that, for example, is hidden at the base of a tree might be very difficult, if not near impossible to find if there's a foot of snow on the ground. On the other hand, a small geocache that is hanging from a tree branch would still be easily findable even in deep snow or ice. Cold and snowy weather does not stop serious geocachers, so this icon is incredibly helpful for planning winter jaunts.
There's another really handy thing about this icon though that is helpful all year round. You see, it gives you a big hint - if a geocache has the snowflake icon, then you automatically KNOW the geocache is NOT hidden on the ground - it's got to be at least a couple of feet off the ground in order to have this attribute! Cool, eh?
Sometimes if we're having trouble finding a geocache first I'll read through the logs to see if anyone gives away any hints as to where it might be. Then I look at the attributes and see if I see that snowflake. Sometimes all you need is just one little hint for the lightbulb to go off in your head and score a find.
Of course you can always resort to decoding the hint, but sometimes even with the hint that find is elusive. Gotta use every clue you can get! :-)
Speaking of that, we're heading out today to try again for a geocache that DH DNF'd last week. Despite all his tricks to extract hints from the geocache page, he still couldn't find it. He was out by himself (well, the dog was with him) and he called me from the trail to look at the page on Geocaching.com to see if I could come up with any ideas - we call that "phone a friend". We'll see if we can find it as a team today...