What are the disadvantages of sand dunes?
Sand dunes can impact humans negatively when they encroach on human habitats. Sand dunes move through a few different means, all of them helped along by wind. One way that dunes can move is through saltation, where sand particles skip along the ground like a rock thrown across a pond might skip across the water’s surface. When these skipping particles land, they may knock into other particles and cause them to skip as well. With slightly stronger winds, particles collide in mid-air, causing sheet flows. In a major dust storm, dunes may move tens of meters through such sheet flows. And like snow, sand avalanches, falling down the steep slopes of the dunes that face away from the winds, also moving the dunes forward. Sand threatens buildings and crops in Africa, the Middle East and China. Drenching sand dunes with oil stops their migration, but this approach is highly destructive to the dunes’ habitat and uses a finite resource. Sand fences might also work, but researchers are still anal
