I've seen them out several times in mid-winter.
One of the neat things I've seen and a missed opportunity for me was seeing multiple grizzly dens and not doing anything about it. I was hunting Unit 13 in the spring (last of April, first of May) and could see five dens on the mountainside across the way from me. Black holes with muddy trails stood out like a sore thumb on that white snow. If I'd have had a clue as to what I was doing, I would have camped out right there and kept a watch on those dens. I wound up getting a large boar later in the trip so it all worked out.
I occasionally see black bear sign here in the winter during a thaw but there's no danger in it,