Given is an illustration that reveals the process of dunes growing. There are three stages for sands gradually pile up to a huge dune, with a essential element wind.
Before the sands roll to the right place blowing by the wind, the bed of sands is a plain dry ground embedding several wet parts. Next, the wind that came from a particular direction warps the surface loose sands, pulling forward till they attach to the wet panel. Then, the late arrival sands stack on the former sandy structure due to the stronger winds. Meanwhile, some sands hanging on the outer of the early immature dune will be scraped down, joining the travel of drift before sticking to the another dune.
Time passed, and in the last, the dune had already accumulated much sands as the wind couldn’t disperse it. The amount of the dune is impacted by the direction of wind or the location of wet sand. In comparison, the dune that straightly closed to the direction of the wind grows larger than others.