From Sansa's Chapter, a Storm of Swords
She threw back the shutters and shivered as gooseprickles rose along her arms. There were clouds massing in the eastern sky, pierced by shafts of sunlight. They look like two huge castles afloat in the morning sky. Sansa could see their walls of tumbled stone, their mighty keeps and barbicans. Wispy banners swirled from atop their towers and reached for the fast-fading stars. The sun was coming up behind them, and she watched them go from black to grey to a thousand shades of rose and gold and crimson. Soon the wind mushed them together, and there was only one castle where there had been two.
She heard the door open as her maids brought the hot water for her bath. They were both new to her service; Tyrion said the women who’d tended to her previously had all been Cersei’s spies, just as Sansa had always suspected. “Come see, ” she told them. “There’s a castle in the sky.”
They came to have a look. “It’s made of gold. ” Shae had short dark hair and bold eyes. She did all that was asked of her, but sometimes she gave Sansa the most insolent looks. “A castle all of gold, there’s a sight I’d like to see.”
“A castle, is it?” Brella had to squint. “That tower’s tumbling over, looks like. It’s all ruins, that is.”
So, two towers... when the sun rises they change colors from "black" to "grey" to "rose, gold, and crimson." Then they crash together leaving one castle, "made of gold." Then it tumbles over all in ruins.
Could this be a description of the Twins and House Frey? While I don't know whose colors are "black," grey is a color of House Stark. House Frey side with Robb Stark, before the Red Wedding. And then sided with Tywin Lannister, whose colors are crimson and gold (not sure about 'rose').
The remaining description might be the fate of the Twins, destroyed and left with one standing, before it to is ruined.
Also, has anyone ever thought of the fate of Ice as a portent of things to come? Ice was the ancestral sword of House Stark, taken by Tywin Lannister it was forged into two blades and given a new coloring, it was suppose to be crimson but ended up as 'waves of night and blood upon a steely shore.'