Sastrugi breaking equipment—ripples and waves are often undercut and the surface is hard and unforgiving, with constant minor topographic changes between ridge and trough. The words "sastrugi" and "zastrugi" are Russian-language plurals; the singular is "sastruga" or "zastruga". The form "sastruga" started as the German-language transliteration of the Russian word заструга (plural: заструги). A Latin-type analogica singular "sastrugus" is used in various writings on exploration of the South Pole, including Robert Falcon Scott's expedition's diaries and Ernest Shackleton's "The Heart of the Antarctic". Under the action of steady wind, free snow particles accumulate and drift like the sand grains in barchan
Surface wave detection by animals ridges; this was shown with electrophysiology. The same experiment also showed that adding ridges to neuromasts that did not previously have ridges also altered the receptive fields for those neuromasts. This suggests that local water flow is important in direction detection. "A lineatus" and other surface wave detecting fish have a limited range in which they can detect surface waves. The ratio of source distance/swim distance ranges between 0.84 and 1.20, and the means range from 0.98 to 1.07. This translates to an accuracy of 85% or higher when stimuli are 6–19 cm from the fish, decreasing to 76% at