This trophy is meant to unlock when you load back to the story in the snow (after the avalanche you have extra story and then you end up back to just after it happened). For me however it didn't unlock first time. I had to start a new game and get the that point again.
From reading about on TA. One of the guides suggests you can do Chapter Replay for Siberian Wilderness to get to this point quicker if you need to make it unlock.