"Hammerfall"

Due to lack of heat in my apartment, I did not get any new sketching done since Tuesday (when I mostly did housecleaning, cooking, and a terrible practice self-portrait). My fingers are too cold.
So, here are some week-old preliminary sketches for a painting I'm planning, inspired by "Lucifer's Hammer".

I did some rough sketches (not scanned) to get some layout ideas, and then layered together some reference photos to make sure the composition will work. The trees are currently only scribbles I'm still working with.

My roommates were kind enough to dress up in some backpacking gear and pose for me.