In winter, rivers and lakes can freeze – this is nothing unusual.
However, if a perfect circle appears on the frozen surface of a river and begins to slowly rotate, it is indeed very strange.
Recently, many people were surprised to see such a circle on the Betra River (the name of the river varies slightly across different sources, likely due to local languages) in the Republic of Bashkortostan, Russia. On the frozen surface of the river, a perfectly round circle is slowly spinning.
This is the video:
Source: Kirill Bakanov.
Internet users were astonished by this mysterious circle. Some commented that it looked like a portal to another dimension, as seen in movies or fantasy stories. Others felt it resembled a supernatural phenomenon.
So, what is it really?
This phenomenon is aptly named after its “appearance”: Ice Circle. In winter, in extremely cold regions, if the conditions are just right, this unusual circle will appear.
The Ice Circle is also known as a “ice disc,” “ice pan,” or “ice cake,” formed in water when ice accumulates in the middle of a current, precisely where the water swirls, according to Tree Hugger.
An ice circle formed on the Presumpscot River in Westbrook, Maine, USA, in January 2019. (Photo: Tina Radel/ City of Westbrook via AP).
The website EarthSky explains that water eddies tend to move in circular paths. In winter, ice crystals in slow-moving water can gradually coalesce to form a “circular carpet” of ice. The current keeps this ice disc in place while it rotates slowly. As the disc spins, it collides with other pieces of ice and essentially gets “polished” until it becomes perfectly round. The result is a circular ice disc with surprisingly smooth and neat edges.
Here is a video of another ice circle:
(Source: JJ).
Ice circles are a very rare phenomenon. A report about an “ice cake” on the Mianus River in the United States in 1895 is considered the first recorded instance of this phenomenon.
