According to geography portal Geo Lounge, Ice circles are unique phenomena that occur in rivers, streams, and creeks all over the world. Most go unnoticed but a few have been seen by people and captured on video or in pictures. Ice circles are rare and form under very specific conditions that often change rapidly, making ice circles quick forming and quick to disappear as well.
Ice circles are also known as ice disks or ice pans. They always form in cold climates and have been recorded most frequently in North America and Scandinavia, although ice circles have been seen in England and Wales as well. Ice circles can vary in size depending on the eddy and the weather, but ice circles have been documented that are 50 feet in diameter.