What causes sand ripples? According to Weatherscapes, running water interacts with sand surfaces - like the waves rushing on a beach. The sand may show a high degree of ordering by forming ripples. Usually these sand ripples are most obvious about 20-50 cm below the water along a beach, but they may also be seen on shore. The fluid dynamics of the water creating the ripples is similar to the formation of gravity (windshear) waves of clouds in the atmosphere.
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