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
Tropical wave tropical waves can extend northward as far as the desert southwest of the United States, producing spells of intensified shower activity embedded within the prevailing monsoon regime. A screaming eagle is a tropical wave whose convective pattern loosely resembles the head of an eagle. This phenomenon is caused by shearing from either westerly winds aloft or strong easterly winds at the surface. These systems are typically located within 25 degrees latitude of the equator. Rain showers and surface winds gusting to are associated with these waves. They move across the ocean at a rate of . Strong thunderstorm activity can