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
Surface features of Venus parabolic excavation cones and flows of lava-like debris. Recent Magellan images show over 6000 aeolian landforms, including dunes (or "undae"), wind streaks, and yardangs. Undae and yardangs have direct analogues on Earth and the process that creates them here can be applied to those seen on Venus. Large dune fields have been identified on the surface and the dunes range in size from meters to hundreds of meters. Similarly, yardang fields may exist in locations such as Mead crater. Wind streaks are parallel linear streaks that form as prevailing winds erode the surface geology. These features illustrate the erosive effect