I was out and about mining in the caves near Riverrun and I've never had this happen before, but I popped up to the snow-covered top part when I started swinging away at this spot. I'm including a screenshot for location data. Not too worried but it was a surprise.
This is due to someone in the house banning/ejecting players who come within proximity of their house, it goes through cave floors unfortunately - and a few people have figured this out, and now just run macros while afk..