Thanks for the link and the quote Ragnorak! I think you were the poster I was thinking of that noticed the similarities between this scene and snow Winterfell (I should have known).
From your post in that thread:
Clouds are the source of snow and for Sansa snow is the taste of innocence and dreams. Both this chapter and Snow Winterfell open with Sansa dreaming of home and in both chapters she throws open the shutters to make her discovery. Both have night fading into dawn. This time she just observes while the next time she goes out and actually builds her castle from the snow that falls from the clouds.
The wispy white banners are a recurring image with Jon although they are usually made snow or ice. I noticed in the Tyrion reread that even his trip north with Jon contains an image of a snow banner:
When the wind blew from the north, long plumes of ice crystals flew from the high peaks like banners
The castles start as black and grey the colors of the Starks and the Nights Watch. Would blue be one of the thousand shades of rose? Is that reaching?
So we've got the wispy snow banners (that we could connect with the snow and ice of the wall)...
... but then we've also got a wisp above Winterfell.
From Bran's very moving last glimpse of Winterfell:
Bran turned in his basket for one last glimpse of the castle that had been his life. Wisps of smoke still rose into the grey sky, but no more than might have risen from Winterfell’s chimneys on a cold autumn afternoon. Soot stains marked some of the arrow loops, and here and there a crack or a missing merlon could be seen in the curtain wall, but it seemed little enough from this distance. Beyond, the tops of the keeps and towers still stood as they had for hundreds of years, and it was hard to tell that the castle had been sacked and burned at all.
So we've got a wispy 'banner' associated with Winterfell here. I think this connects with the wispy banners in Sansa's vision.
Edited by greensleeves, 24 April 2013 - 07:17 PM.