Sastrugi

[1] Sastrugi are distinguished by upwind-facing points, resembling anvils, which move downwind as the surface erodes.

The form sastruga started as the German-language transliteration of the Russian word заструга (plural: заструги).

[4] A Latin-type analogical 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.

On the windward side of a ridge, the base erodes faster than the top, producing a shape like an anvil tip pointing upwind.

The locations of sastrugi are fixed by March in the northern hemisphere and may be linked to the formation of melt ponds.

Wind sculpted snow near South Pole Station, forming sastrugi features.
Large sastrugi seen in radar image around the south edge (left side) of Lake Vostok in Antarctica ( RADARSAT , NASA ). White and black colors on sastrugi are not lights and shadows, they demonstrate difference in radioreflectivity of snow deposits on the windward and leeward sides of a sastruga.