I just scanned through this excellent document. I'm from Chicago and now I live in Arkansas and I won't drive on the ice if I can avoid it. In Chicago I drove on ice all the time and I can deal. It's all the other drivers on the road I can't deal with.

Larry covers a lot of ground in this short pdf and as far as I could tell it's all based on actual knowledge of wintry conditions. So if you're pulling wagons across an iced over river you can test the thickness of the ice, see if you're near a fork or other turbulent area. Do a visual examination for ice clarity or cloudiness and then if you feel safe proceed with caution.

If you don't do these checks the DM is going to roll for them and your wagon and supplies may end up at the bottom of the river. I hate when that happens. don't you?

Thanks Larry! Glad you liked it!