Posted at: 11/26/2013 1:39 PM
Updated at: 11/27/2013 11:17 AM
By: The Associated Press
Retired engineer George Loegering was out hunting with relatives over the weekend when he came across a spinning disk of ice in the Sheyenne River -- a weather phenomenon experts say likely was caused by cold, dense air, and an eddy in the river.
This ice circle is entirely natural and quite rare. It is the result of an eddy in the slowly-moving river. As the river began to freeze, the eddy froze as a perfect circle.
Ice circles are rare because they require just the right conditions: The river must be at the point of freezing, an eddy must be present and the current must be slow.
If the water is too fast, there is too much turbulence and the eddy is disrupted. If the eddy swirls too slowly, the river just freezes over without the circle.
It formed over the weekend on the Sheyenne River about 10 miles Southwest of Leonard, ND.
"It's a pretty cool one," one weather expert said.
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