A yardang (Kalout) is a topographical feature that has been carved out of a surface by the wind. The word is derived from the Turkic word yar, which means ridge or steep bank. On Earth they are most commonly found in deserts where there is a sand supply, which abrades the surface when moved by the wind, and soft sedimentary rocks that the sand easily erodes. Over time, the sand wears down the surface into beautiful streamlined shapes that are aligned with the prevailing sand-moving winds.
Iran is famous for mega yardangs in Shahdad, Kerman, where thousands of tourists visit every year. In the western part of Dasht-e Lut lie some of the world’s most prominent yardangs. Rising up to 282 feet (80 meters), these streamlined ridges have been carved by the wind out of the silty clay and sand lining the desert floor. Lying parallel to the prevailing north-north-west winds, the yardangs are separated by troughs measuring 330 feet (100 meters) or more. The crests or summits of the largest of these yardangs are rounded or flat; all others are narrow.
