Seif
Also called: Seif dune · Topic: Landforms and their Evolution: Rivers, Groundwater, Glaciers, Waves and Wind · NCERT: Class 11, Ch 6 "Landforms and their Evolution"
Meaning
A seif is a sand dune like a barchan (a crescent-shaped dune) but with only one wing or point. It forms when the wind changes direction. The changing wind builds up one wing while the other does not grow. This single wing can become very long and high. The name comes from the Arabic word for "sword", because of its long, sharp shape.
Example
Seif dunes are found in the Sahara, for example in the deserts of Algeria and Libya, where they stretch as long, sharp ridges of sand.
Don't confuse with
- Barchan: has two horns pointing downwind and forms under a steady, moderate wind. A seif has only one wing because the wind changes direction.
- Longitudinal dune: a long, low ridge that forms under a steady wind with little sand.