Large rivers usually don’t completely freeze over. There may be ice on the surface, but underneath the river still flows. The Mississippi is like that. It’s beautiful to look at on a sunny day, but every few seconds, you hear the ice crack-pop-snap from the energy beneath. I would be afraid to walk across a large river covered over with ice. It’s not what it seems.
My great grandfather did some bootlegging back in the day. During the summer booze crossed the Detroit river in boats and during the winter they drove.