In reply to Jon Bracey:
> Winter ascents are often much tougher, and thats why they are called 'winter ascents'.
> Traditional alpine grades are very rough and ready, not giving you much detail of the hardest technical pitches, hence the additional info of rock grades and what you refer to as the Damilano system.
All fair comment.
But I can see where a lot of other posters are coming from.
A UK rock grade is for good summer dry warm conditions, it obviously feels harder in poor weather, but its too much hassle to give dual grades or whatever. Some guidebooks may try to give extra info, like "very hard if damp".
I presume the Alpine grade is for good summer alpine conditions.
Again some routes are particularly harder in winter, the Walker sounds like one of them.
Wise boB often used to point out that winter soloists, linking the classic three north faces, rarely did the Walker but some other route on the GJ.