Sand wave

A sand wave is a lower regime sedimentary structure that forms across from tidal currents.

[1] Sand waves are formed through the action of the wind or water (through waves or tidal currents)[2] and are a product of unidirectional flow.

Sand waves are the result of a mean flow velocity between 40 and 70 cm/s.

Sand waves also form underwater.

[3][4] Media related to Sand waves at Wikimedia Commons

Sand waves
Sand waves under water in a shallow part of Gullmarn fjord