As I have noted in the comments, Paul and I spent the weekend in (chilly) northern Wisconsin snowmobiling. It was a most excellent time. Below are some pictures from the quick trip, with some explanations (as I am pretty sure this is not something people engage in, in most places in the country). There is also a short video, which should give you a bit of a feeling for what it is like.
Date: January 17, 2017
Length: 1.8 Miles
Now, the video. The sled ahead of us is my dad; I’m riding on the back of our snowmobile with Paul. We pass two other people part way through the video as we cross a bridge; you can see the latter of them putting up a fist. It indicates he’s the last person in the group. You can see from the video that these are winding paths (and this one isn’t particularly windy), so this tells you that no one else is coming around a bend unexpectedly. You can also see some ‘traffic signs’ on the right hand sign before we go around a curve. Even though it’s a path not meant for cars, the same signs get used.