I agree with my fellow posters, but also would like to know how you made the mountain, WM? Did you use a painted shader to get the snow in the finer gullies? There just a tiny bit of stretching of the snow near the top of the mountain where you displace the snow layer up, perhaps due to a (too) fine mask. And, IMHO, it seems a bit like a toy landscape, a small area with a 'big' landscape, which is nice in itself, but if you strive for reality some more haze would probably increase that.