This coast is an offshore bar.

The throng uttered a sound like a wave breaking gently on an offshore bar.

Later, the modern coastline "was established through the buildup of an offshore bar", and the ridges of the site became surrounded by a water-filled lagoon.

Longshore currents also commonly create offshore bars, which give beaches some stability by reducing erosion.

But if the necessary very gentle offshore gradient can be produced on any type of shoreline it is quite likely that offshore bars may form.

The usual explanation of offshore bars is that given by Johnson (1919) and the stages of formation envisaged by him are shown in Fig. 8. 18.

Given a slight negative movement of base level, underwater sandbanks may appear above high tide level and could be converted into offshore bars by wave action.

Scolt Head Island, the most fully developed offshore bar on the Norfolk coast, has had a history comparable with the above idealised conditions.

Much of the sand that moves off the beach ends up in offshore bars, and in calm weather, some of the sand will move back onshore.

For example; when a beach in equilibrium erodes during a storm it forms an offshore bar that in turn forces waves to break over it.