Why are sand dunes asymmetrical?

Sand dunes are asymmetrical primarily due to the effects of wind direction and speed. The windward side, which faces the wind, is typically more gently sloped as sand accumulates gradually, while the leeward side, or slip face, is steeper and forms more abruptly as sand cascades down. This difference in slope is a result of the erosion and deposition processes driven by the constant movement of sand by the wind. Additionally, variations in vegetation and moisture can further influence the shape and asymmetry of dunes.