The summer beach is covered with a layer of sand that is moved south by the longshore currents and onshore by low waves. The winter beach is denuded of sand by high storm waves. Cobbles are heavier and remain on the beach. The wave-cut platform underlying the mobile sediments is visible in the foreground.

Rocky beaches occur where coastal cliffs erode and crumble into large rock deposits along the the shoreline, blocking the build up of smaller, sandy sediment. Rocky beaches are areas of rich intertidal biodiversity.

How does the beach face change from winter to summer?-The beach face changes from winter to summer because in winter the beach appears as having less sand than in the summer. In the summer, there is a full beach face.

In winter, prevailing winds shift and waves become higher and more frequent. These winter waves pick up sand from the beach and move it offshore to form sandbars that buffer the beach from storm erosion because they cause waves to break further offshore.

Constructive waves

Destructive waves are thus more common in winter than in summer, and usually occur in exposed bays. Less sediment, sand and geological material becomes available to build-up the beach due to the increased erosion brought about by destructive waves.

Destructive waves have a large wave height and short wavelength. They have tall breakers that have a high downward force and a strong backwash. Their frequency is high with between 13 and 15 waves per minute. Their strong downward energy helps erode beach material and cliffs.

A winter beach is lower, may not have a berm, and often shows signs of loss of beach grass. Winter beaches are generally steeper and narrower, while in the summer beach, smaller, calmer waves dominate, and beaches are generally wider and have a gradual slope.

The size and energy of the waves, the strength and direction of the wind, and the type of rocks along the coast create a range of coastal landforms. Features of coastal erosion such as cliffs, wave-cut platforms, caves, arches, stacks, headlands and bays are formed by powerful, destructive waves.

What are destructive waves? Although a destructive wave’s swash is much stronger than that of a constructive wave, its swash is much weaker than its backwash. This means that these waves can transport beach material back into the sea and lower the height of beaches in winter. Destructive waves destroy beaches.

If the swash is weaker than the backwash (destructive wave), very little sediment is carried up the beach. With a strong backwash, material will be removed and the beach will decrease in size….Wave types.

The sediment falls to the ground as a result of the wind slowing down or an obstacle traps the wind blown sediment. Wind erosion and deposition may form sand dunes and loess deposits.

Water as a constructive force: It is involved in the deposition of sediments. It transports rock fragments, soil, and other debris at a particular area. This process eventually causes them to accumulate and form land features. Water as a destructive force: It is involved in weathering and erosion.