In North Dakota, USA, a senior citizen named George Loegering became a witness to an unusual phenomenon. 
Photos from open sources Last weekend, he went to hunting, then Loegering and noticed a huge circle of ice, with a diameter more than 15 meters, which spun on the surface of the Cheyenne River. A pensioner posted on the Internet a video of the rotation of a huge ice disk. In the comments to the video, an eyewitness says that what is surprising is not the piece of ice itself, but how it rotated. “At first I didn’t understand that it is that. I just stood and considered this surreal phenomenon, “a 73-year-old resident tries to explain his feelings. USA. A man saw in the middle of an ice-free lake a large ideal form ice disc. Eyewitness made several photographs, and, remembering his engineering background, calculated the diameter of the disc is about 17 meters. For comments, he turned to to specialists. Hydrologist of the National Weather Service Alain Schlag spoke of a rare hydrological phenomenon: “This is very beautiful a phenomenon caused by a combination of cold air, warm water and a whirlpool in a pond. “It turns out last weekend in the region significantly colder and an unusually high pressure established. The water in the lake was still relatively warm, but the surface grabbed the first ice. The ice failed to forge the whole lake, and he began to float on its surface in small pieces. Circulation water masses in the lake (the notorious whirlpool) drove ice slices into center, and formed from them a large disk of perfect shape. It turns out that the ice disk is not continuous, but consists of thousands of small ice floes? “Yes,” says the hydrologist Schlag. “If you throw in the center of the disk, like an orange, it just goes through it. ”
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