Check out these very neat images taken by Waterville Valley fisherman/outdoorsman, Ray Kucharski.
In an email Ray sent to me along with the images, he described these beautiful – and rather artistic – round ice disks as winter lily pads. Ray wrote, “I have never seen ice formed in 8- to 18-inch circles floating in a river or pond before.”
Update Feb. 6, 2012 … Interesting…Wikipedia has a definition for ice discs!
Ice discs form on the outer bends in a river where the accelerating water creates a force called ‘rotational shear’, which breaks off a chunk of ice and twists it around. As the disc rotates, it grinds against surrounding ice — smoothing into a circle. A relatively uncommon phenomenon, one of the earliest recordings is of a slowly revolving disc was spotted on the Mianus River and reported in a 1895 edition of Scientific American.