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
Galactic winds Galactic winds Galactic winds are high velocity stellar winds. The phenomena is caused by either strong stellar winds emanating from newly formed massive stars or as the result of the effects of supermassive black holes. Galactic winds are strong stellar winds made up of charged particles, ejecta, and varying amounts of hot and cool gas. These gusts are caused by the release of ejecta by massive stars, spiral density waves, or supernovae. In galaxies with active galactic nuclei, galactic winds can also be driven by the effects of super-massive black holes. Galactic winds are considered an important function in the