In Germany, houses with pitched roofs sometimes have "snow fences" in addition to rainwater gutters. I found theses picture:
http://www.arcat.com/photos/trasnow/130048.jpg
http://www.hobotraveler.com/149germany/0013.JPG
http://www.hobotraveler.com/149germany/0014.JPG
The snow piles up on the roof, the fence holds it steady, and this prevents damage to the gutters.
I don't know how much snow you get or how strong the fence needs to be, but this seems like it could be a good solution.
