Barchan dune. (n.d.). In YourDictionary. Retrieved from https://www.yourdictionary.com/barchan-dune
A large, crescent-shaped dune lying at right angles to the prevailing wind and having a steep, concave leeward side with the crescent tips pointing downwind. Barchan dunes form on flat, hard surfaces where the sand supply is limited. They can reach heights of up to 30 m (98 ft) and widths of 350 m (148 ft).