I got a call from Dean Kjerland at Art On Water Gallery yesterday, alerting me to some lily pad-like ice floes circulating below the Ames Mill dam. He wondered whether they were pollution related. Rob Schanilec at By All Means Graphics theorized that last summer’s repairs to the adjacent retaining wall may be causing a different circulation pattern in the water, as he doesn’t remember this phenomenon occurring.
Wikipidia has an entry on ice circles. Evidently, there are two different types. More photos here.
Update 12/25: Patrick Enders emailed me this photo of a single large ice circle at the foot of the dam that he took with his iPhone about 1-2 weeks ago. He says in a comment below that there were two of them.
Update 01/12: Another batch of ice circles has formed during the current cold snap:
A pair of large ice circles (about 20 ft across) were slowly rotating below the dam earlier in December. One eventually lodged below the bridge, while the other one floated on alone. I’ve sent you picture, in case you’re interested.
Dummies… it’s ice frogs. Very large ice frogs. They’re massing in preparation for something. Not something anyone wants. Be warned, Northfield. The ice frogs cometh!
I looked at the pictures on “here”, and the one fellow crouched on the edge of the ice on that river is asking for a dunking, or possibly one of the ice frogs will take him out!
Thanks, Patrick. I’ve added your photo of the single large ice circle to the blog post above.
FYI, all the ice circles were gone when I went by the dam yesterday morning at about 8:30 am.