This is open water on a river, with ice forming on a rock. This is a set of rapids in the South Kawishiwi River. The moving water in the rapids keeps ice from forming over the top-- even on cold winter days. Warm water from the bottom of the river is churned up in the rapids. Ice forms on the rocks when water splashes on them.
Clue #1 This is wet.
Clue #2 Something is moving around the white object.
Clue #3 We can't dogsled here.