Longshore drift occurs when a wave breaks, lifts sand into suspension, and then throws a pulse of sand-bearing water (swash) up the slope of the beach. If the wave breaks on the beach at an angle, the swash travels simultaneously up the beach and along the beach in the direction of the wave's original motion.

What causes the longshore drift to occur?

Longshore (littoral) drift is the movement of material along the shore by wave action. It happens when waves approach the beach at an angle. ... The backwash (waves moving back down the beach) carries material back down the beach at right angles. This is the result of gravity.

What is longshore drift and how does it occur?

Waves that hit the beach at an angle carry sand and gravel up the beach face at an angle. When the water washes back the sediment. is carried straight back down the beach face. Individual particles are moved along the beach in a zig zag pattern. This is called longshore drift.