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 wave detection by animals source, the less arc angle will be measured in the distance between the neuromasts). However, there is no evidence of a neural circuit that performs this calculation, and other researchers suggest that the distance between any pair of surface wave neuromasts is too small ("A lineatus’s" head is only 1 cm wide) for the calculation to be made accurately, and then at distances from the stimulus less than 7 cm. The accuracy predicted by a time-difference mechanism (using triangulation of the wave source based on curvature of wave front) doesn’t match actual accuracy. Additionally it has been shown that if