drift is caused by wave and current action. It is the primary method of
sediment transport along the beach. The direction of this motion is always
parallel to the beach face. On Folly Beach, as well as other islands along
the southeastern coast, the lonshore drift most often moves in a north
to south direction. This occurs because most of the wave hit the beach
at an angle. In the picture below notice how the waves are approaching
the beach at an angle. The yellow line represents the angle of the approaching
waves. The orange arrow shows the direction of the longshore current.