Wadi at Foot of Mountains in Yemen15.1N 46.1E
A wadi is a valley or ravine, bounded by relatively steep banks, which in the rainy season becomes a watercourse. They are found primarily in North Africa and the Middle East.
In this image of southwestern Saudi Arabia and Yemen, several wadi are visible in the sandy area at the foot of the brown mountains just below the image center. These are, from east to west: Wadi Markhah, Wadi Dumays, Wadi Harib, Wadi Raghwan and Wadi Jawf.