When there is too much sand for the headland to hold, or there’s a change in wave conditions, some sand will be pushed around the headland — bypassing it — before continuing its journey up the coast.
This large lump of moving sand is called a “sand pulse” or “sand slug”. The sand pulse needs the right wave conditions to move towards the shore. Without these conditions, the beach in front of the pulse is deprived of sand and the waves and currents near the shore erode the beach.
Headland bypassing was first described in the 1940s. However, only about 20 years ago was it recognised as an important part of the process controlling sand moving along the coast.