Working on a couple winter scenes right now. This is a preview shot for a render that I'll move into production later this evening. Render time was 90 mins at 800x500, Detail 0.75, AA 4, 32 Atmosphere Samples.
The terrain is very simple, with a snow shader based on stuff posted to this forum.
Postwork: HDR conversion (Gamma 1.1, Exposure 1.2)
Looks barren, stark and very cold... would not like to be lost here.