Late last December we had a cold snap followed by several days of gradual warming. These are perfect conditions for river ice to form in fasciating shapes that constantly change as they grow and then melt away.
Update: four weeks now after my back injury I've healed quite a bit but have a long way to go. I still can't stand or sit upright for more than a few minutes. That basically means I can't *do* anything for more than about five minutes or so. Another two or three weeks will likely be needed to get more or less back to normal. Then I'll have to deal with recovering from 6-7 weeks of forced inactivity.