know about them until they were seen on satellite images, in which they can resemble large fingerprints. The patterns are not visible from the ground, but wave forms are present in the snow. Megadunes can be 26 feet (8 m) high and 4 miles (6 km) across. They form quite differently than sand dunes in the desert. Air that moves downhill is called a katabatic wind , and megadunes form in these steady, continuous winds. The dunes form slowly, very much like maple syrup running off a pancake. One side of the dune is icy, almost like glass. The other side of the dune is a wavelike structure of snow. Although beautiful, scientists who have explored them say the megadune surface is very rough, like sandpaper. Sun cups are hollowed-out bowls in the snow. Sun cups can form during snowmelt in several ways. As the solar radiation hits the surface on a bright sunny day, the sun cup can form because
These breathtaking snow formations are called sastrugi. They are formed by wind patterns that blow across the snow.
The New Weather: Amazing Weather Facts
Made with FlippingBook Ebook Creator