Cool. I love the glow you've added to the mist the dragon's heat is creating. As for the mountains, I like that they are all ice covered yet clearly stone underneath, it gives a good sense of how high in the ranges this beast is.
I agree with the people that have commented on the snow looking like cobwebs. That was the first thought that I had when I saw it. I half expected a giant spider to be chasing him up the mountain, like they were fighting over a cave or something. I love how realistic it is. The background is still fairly abstract, but you can see the difference between the clouds and the mist swirling in the mountains, and the blurring on the mountains in the background add to feeling of perspective and distance. Very nice work.