Ice circle

[3] A relatively uncommon phenomenon, one of the earliest recordings is of a slowly revolving disc spotted on the Mianus River and reported in an 1895 edition of Scientific American.

The dense water then sinks and creates its own circular motion, causing the ice circle to rotate.

[10] An unusual natural phenomenon, ice disks occur in slowly moving water in cold climates and can vary in size, with circles more than 15 metres (49 feet) in diameter observed.

An ice circle of approximately 15 m (50 ft) in diameter was observed and photographed in Lake Katrine, New York on the Esopus Creek around 23 January 2014.

In Idaho, extreme weather led to a rare sighting of an ice disc on the Snake River on 22 January 2014.