Sure, just keep in mind that the first couple snowfalls of the season usually melt off some, and subsequent snow coverings may not allow the rocks beneath to dry out sufficiently. Ours was early in the season, but I imagine it could still happen if the moisture isn't drawn off of them before they freeze up later on.

We've since moved on to toting well maintained concrete blocks up ourselves. Those we know what there condition is, but in a survival situation you make do with whatever you can find and just be careful.