16 January 2019
Ice disks - updated
I've previously posted photos of interesting ice formations, including round ice floes in Russia and a "creek circle" in Canada. This photo above was posted at the cosmos of enlightened vision; the disk was reportedly seen on the Salmon River in Idaho.
Related: Frazil ice at Yellowstone (video).
Reposted from 2011 to add this massive one:
This disc formed on the Presumpscot River in Westbrook, Maine. It's about a hundred meters in diameter. Details, plus a rather unexciting video at Gizmodo, via Neatorama.