I've been putting the idea of a winter hang in my mind and remembered an incident while walking to the top of Tumalo Mt. A piece of ice fell off a branch and hit me on the head. It actually broke skin and caused a little blood. My hiking partner asked what to do and I said, "Put ice on it." ... which caused us to laugh ourselves silly.
So I understand about looking up to make sure there are no branches to come down. But in the winter, perfectly healthy branches are loaded with snow.
So it seems there are three choices (a fourth choice, not going, is out of the question).
1) bring extra long suspension line so you can hang between two trees that are pretty far apart - so you are more away from overhanging branches
2) spend a lot more time looking for a site that offers spindly - but still strong enough for a hammock - trees. That is, trees with not enough upper branches to allow a snow load
3) take the risk - the snow hasn't come down so far and odds are it will come down when it is warmer, in the afternoon, rather than during the colder temperatures at night.
So what's the deal with winter camping. Do you ignore the snow and follow the encouraging words of that wise philosopher, Christie Brinkley, "Well, are you gonna go for it?" (National Lampoon's Vacation, circa 1983)?