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
Rogue wave also recently (2012) proven the existence of "rogue wave holes", an inverted profile of a rogue wave. In maritime folk-lore, stories of rogue holes are as common as stories of rogue waves. They follow from theoretical analysis but had never been proven experimentally. In 2012 the ANU published research confirming the existence of rogue wave holes on the water surface observed in a water wave tank. On a smaller scale, kayakers call unpredictable 'exploding waves' caused by wave interaction "clapotis". There are a number of research programmes currently underway focussed on rogue waves including: Because the phenomenon of rogue waves