Do not go on river ice or rapids

You should never move on river ice or ice shelves near rapids under any circumstances. River ice remains fragile throughout the winter due to the water flow. Flowing water continuously erodes the ice from below, forming a fragile shelf-like structure over the river. The treacherous nature of river ice is further increased by the snow that falls during winter, which acts as an insulator, preventing the formation of new ice regardless of the temperature or cold spells. At worst, the river is eventually covered only by a layer of snow.