Thanks, Trigonomicon! It's not very structured and it varies a lot. I've started exploring composition ideas on paper and digitally lately. Usually about 4-6 of them, sometimes a lot more. For this piece, I had a clear idea so no exploration was needed. I sometimes go back and forth between early sketches and SketchUp to make sure complex structures are in perspective. As soon as I feel that motivation is running out, I make a short list of things that must be fixed and give myself a time limit to avoid burning out. I'm getting old and I'm in a hurry. 
This is fantastic! And I'm very impressed by how quickly you're making these, what is your workflow like?
Thanks! Good call, the aurora in the Long Dark was a big inspiration for this. I liked the idea that it made the animals go insane. Even slightly reminiscent of the evil yellow-green light in Sleeping Beauty. I also like the idea that natural phenomena can drive people mad, either like some kind of cosmic horror as with Lovecraft, or as in Sunshine (2007).
Reminds me of some of the aurora vibes in The Long Dark,nice job!
Beautiful colors and atmosphere. Very heroic.