This was an interesting phenomenon. With a change in temperature, the ice sheets had shifted and the water at this point of the river seemed to have to decide whether to go over the ice or under it. Most of the water went under the ice and seemed to pull at the surface water. The effect, which I tried to capture here, was a vortex of water which rotated on the surface before eventually being pulled under. It looks even nicer with the semi-transparent ice sheet which turned the surface water a slightly blue colour.
Idelly, I would have liked to do a longer time exposure, but I did not have a tripod with me and the sky was so bright that anything longer would have been blown out. I am happy with what I got.
Tamron 70-200mm f/2.8 @ 98 mm
1/8 sec, f/32, ISO 250