Long shore drift is the process by which sediment is moved along a beach in the direction of the prevailing wind. Sediment is sand, gravel and other small particles that make up a beach and seabed. The prevailing wind is the direction that the wind most commonly blows in. The wind creates waves which flow up onto the beach at the same angle as the prevailing wind. This is called swash. The waves then flow back into the sea, perpendicular to the beach - in other words, the water flows away from the beach straight back into the sea, not at any angle. As the swash flows up onto the beach, it picks up sediment and carries it. The backwash then carries it and it is deposited. It does not flow back to where it was picked up. This process gradually moves sediment along the beach in the direction of the prevailing wind.