Sastrugi Sastrugi Sastrugi, or zastrugi, are sharp irregular grooves or ridges formed on a snow surface by wind erosion, saltation of snow particles, and deposition, and found in polar and open sites such as frozen lakes in cold temperate regions. The ridges are usually perpendicular to the prevailing winds; they are steep on the windward side and sloping to the leeward side. Smaller irregularities of this type are known as ripples (small, ~10 mm high) or wind ridges. Larger features are especially troublesome to skiers and snowboarders. Traveling on the irregular surface of sastrugi can be very tiring, and can risk
The Wave, Arizona grainflow and windripple laminae. The rhythmic and cyclic alternating laminae represent periodic changes in the prevailing winds during the Jurassic period as large sand dunes migrated across a sandy desert. The thin ridges and ribbing seen within the Wave are the result of the differential erosion of rhythmic and cyclic alternating grainflow and windripple laminae within the Navajo Sandstone. These laminae have differing resistance to erosion as they have been differentially cemented according to variations in the grain size of the sand composing them. The soft sandstone is fragile, especially the ridges and ribbing of the Wave. As a result,