Sastrugi or zastrugi are sharp irregular grooves or ridges formed on a snow surface by wind erosion and deposition, and found in polar and temperate snow regions. They differ from sand dunes in that the ridges are parallel to the prevailing winds. These words are plural: the singular is sastruga or zastruga. The word was taken from Russian and has a Russian-type plural. A Latin-type analogical singular sastrugus is used in various writings including Robert Falcon Scott's expedition's diaries, and Ernest Shackleton's The Heart of the Antarctic.

Sastrugi are various surface irregularities resulting from wind erosion, saltation of snow particles and deposition. Ranked by increasing size, these irregularities are known as ripples (~10 mm high), wind ridges, barchans and sastrugi (up to 1 meter high). Larger features are especially troublesome to skiers. Travel on the irregular surface of sastrugi can be very tiring, and can risk breaking skis—ripples and waves are often undercut, the surface is hard and unforgiving with constant minor topographic changes between ridge and trough.

References

• Grey, D. M. & Male, D. H. (editors). (2004). Handbook of Snow: Principles, Processes, Management and Use. ISBN 1932846069
• Shackleton, Sir Ernest Henry. (1909) The Heart of the Antarctic: Being the Story of the British Antarctic Expedition, 1907-1909 ISBN 978-0786706846