Pretty significant when you add the conversation I had with a game warden two or three years ago. I asked him where the animals winter and he said that they find south slopes and hunker down for the winter without migrating that much. This surprised me, I would have thought that they would migrate out of the Church into the valley's but he said they didn't. In fact, he said that the animals move very little. He also said (and a Montana Bio confirmed during another, separate conversation) that Montana's deer heard and some elk migrate back over the state line into Idaho for the winter.
I am guessing that those animals winter in some pretty sparse ground and get landlocked into relatively small south slope "pastures". I would also imagine that they are easy pickings for predators during that time......