In reply to Offwidth:
> If we want to preserve routes as best we can some sort of ethical pressure is a necessity.
It's got to be true that gardening unfrozen turf will remove/kill it. However, if we're thinking strictly in terms of route preservation, the rock tends to get considerably more scratched up when covered by anything that won't solidly take a crampon (i.e. powder, hoar, rime, thin/cruddy ice, thin neve etc.) than when totally bare. Of course, I'm not proposing a dry-tool-the-classics sesh - there are plenty of good aesthetic reasons for climbing in wintry conditions, the key one being that we like winter! - but I am saying that the "don't damage the rock" thing just doesn't add up.
(Not that this is anything that hasn't been said before a thousand times on here and elsewhere, no doubt!)