Interesting thread! My first reaction to the photos was 'bear'. Try Google Images and search for "wolverine (or otter, or bear) tracks in snow". What stood out for me is the 'diagonal stagger' of the wolverine, where the axis of one set of four tracks was seldom parallel to the travelway axis.
River otter tracks I've seen in powder were close to circular, a bit smaller, and show the classic weasel-family paired track, where the hind feet mostly land on the front prints. They also tend to be blurred by belly drag if the snow is very deep or soft. The OP location & elevation don't seem right for otter either, though I spent several days last December tracking one around Reflection Lake at MRNP, even up drainages onto Mazama Ridge at over 5000 feet. Never actually saw it, but it was cool to see how it would go down one creek hole and come back out another. I think perhaps it was after frogs.
...I'd hate to see the size of the marmot that made 4-5 inch long tracks. With my luck he'd find my pack and luch when I went up for another lap.
That would be a truly formidable marmot to leave tracks that large! I once had a marmot destroy my pack straps for the salt while I was lapping Hurricane Hill. Three miles is a long way back with chute cord shoulder straps; I always keep my pack with me since.
