There can also be heaves in the lake, rather large ones, and if you don't know/see them, you could take a bad tumble. Almost happened to me and my group some years ago. We were staying at what was McConnelys, the furthest south resort on the lake at that time. We left Root Cellar [nite] and headed back only to encounter a huge split/drop in the ice. Scary, to say the least. We were saved because we seemed to hit it from the right direction. Next day we looked and measured about 10" drop, so if we d have hit it going north it would have trouble.