How do windward and leeward slopes differ on a sand dune?

On a sand dune, the windward and leeward slopes differ significantly in their formation and physical characteristics:

• Windward Slope: This is the side facing the wind. As wind moves up this slope, its near-surface velocity increases to compensate for the drag caused by the sandy surface. Sand is primarily eroded from this side and transported toward the crest of the dune.1
• Leeward Slope: This is the side sheltered from the direct wind, often referred to as the slip face. As wind reaches the crest, it separates from the surface, creating a "dead zone" where the air cannot follow the slope. Sand transported up the windward side falls into this zone. When this slope reaches the angle of repose—typically about 32° to 33°—the added sand slips down, allowing the dune to maintain its form and migrate forward over time.12

Essentially, the windward side acts as the zone of erosion and transport, while the leeward side serves as the primary zone of deposition.1