Meet Nature's Wondrous, Self-Rolling Snow Doughnuts
24 DECEMBER 2020 Found mostly in the open prairies of North America and some remote regions of Northern Europe, snow doughnuts or snow rollers might look like icy man-made structures, but these tire-shaped curiosities are entirely natural. They're very rarely seen because the number of weather conditions that need to be just right for them to form – including wind, temperature, snow, ice, and moisture – is pretty astonishing. So how do they form? It turns out you need: A relatively thin surface layer of wet snow on the ground Under that layer, there needs to be a substrate the wet sno...
Source: sciencealert.com