Right so this is the kind of thing that keeps me up at night (ironically). The no footprints detail is what gets me, because thats always the part people can't explain away. Like sure, maybe it was an animal - but what animal leaves zero trace in fresh snow?
Norway here and we get a fair bit of snow, and I've heard foxes on roofs before, they always leave prints. Always. So whatever this was either wasn't touching the surface properly or it came from above somehow and went back up the same way.
What did the walking actually sound like? Heavy, light, bipedal? That detail matters a lot I think. Some NDE accounts actually describe entities that move without leaving physical traces which is a weird overlap with this kind of thing.
Genuinely curious if anyone else has had this and what they think it was. Post more details if you can remember them.