Unusual ice "pancakes" formed on top of Lake Superior in northern Wisconsin on Tuesday, 28 November, video shows.
According to the UK's Met Office, ice "pancakes" are a phenomenon where discs of ice anywhere from 20 - 200 cm wide are formed creating a unique spectacle.
They are relatively rare, but when they are seen they tend to occur in very cold oceans and lakes such as the Baltic Sea, Antarctica, and on the Great Lakes of the United States and Canada.