Rare 55-Foot-Wide Ice Disc Spins Along North Dakota's Sheyenne River [VIDEO]
A rare 55-foot-wide disc of ice, spinning in North Dakota's Sheyenne River was captured on video by retired engineer George Loegering on Saturday. Loegering, who lives in rural Casselton, about 20 miles west of Fargo, saw the bizarre phenomenon while out hunting with his brother-in-law and nephew. "At first I thought, 'No way!' It was surreal," Loegering, 73, told the Associated Press. "You looked at it and you thought, how did it do that?"
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The apparent disc, which is really a collection of smaller piece of ice spinning around, forms at bends in the river, where the accelerating flow of water creates a force called "rotational shear," which breaks off a chunk of ice, twists it around, and grinds it against the surrounding ice until it looks like one spinning monolith. Though the spinning discs ocassionally make an appearance in the Arctic, Scandanavia, and Canada, they are pretty rare in the United States. Since the air pressure in Casselton on Saturday was a record high for November, the cold, dense air turned the river water into ice. But because the water was relatively warm, the ice formed gradually. Floating bits of ice were captured in the eddy and began to spin.
"It's not a solid piece of ice," Allen Schlag, a National Weather Service hydrologist in Bismarck, told AP. "It's a collection of ice cubes." Schlag said he was surprised by its size, which he said would be more likely on a larger river such as the Missouri. "It's a pretty cool one," he said. "It's actually quite beautiful."
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