From the fresh dirt trailing from this hole, we suspect the marmot is spring cleaning. Be cool if they have a litter. I’m hoping they don’t go messing with the foundations though as this new hole is under the rear deck that we recently pulled up (below the white plastic picket fence in the “Going, going, gone” post).
Here is a good wiki article about Marmots.
I also found some old picks, when I first spotted the hole as I was removing the deck and a hole under one of our foundation walls.