At one time, you could specify cold weather lubrication when a CLA was performed. That's probably a lost skill now. Anyone know of a repair shop that will use special low-temp lubricants? At -30C, not many of my cameras will work. I can always count on Pentax (spottie, kx, MEsuper) and the recently cla'd lenses on my century graphic and 4x5 speed. The more complex MF cameras, (Pentacon Six, Rolleiflex, Yashica) usually seize up after about 2-3 min in that temp, and return to normal when thawed.
Remember too that anything run by batteries is going to fail rapidly when exposed to extreme cold.
Exposed flesh freezes pretty fast too. To keep fingers from freezing, try to find "hunter's mitts". They have a slit in the palm of the mit so you can stick a finger out to squeeze the trigger.