How do dune fields migrate across a desert?
Quick Answer
Wind moves sand grains up the gentle windward side and down the steeper leeward slip face. Repeating this process makes dunes slowly shift position.
The Full Story
Sand dunes migrate because wind pushes grains in a series of small jumps called saltation. As grains move up the windward slope, they are carried over the crest and avalanche down the steeper slip face. This repeated transport causes the entire dune to shift downwind over time. Dune shape depends on wind direction, sand supply, and vegetation, which is why barchans, transverse dunes, and star dunes look different. In active deserts, some dunes can move several meters each year.
Key Facts
YouTube Angle
Suggested video title for this topic:
"Desert dunes are not fixed—they crawl across the land."
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