Generally speaking, a beach is a narrow, gently sloping strip of land, extending landward from a body of water, such as a sea or lake. Depending on the size and shape of the beach, it may be composed of sand, pebbles, rocks, or mud. Beaches are important cultural and recreational features of many places. They are usually occupied year-round by people. The beach may have some kind of infrastructure, such as lifeguard posts or shacks. Some beaches are also closed for periods of time, such as during strong storms.
A beach can be steep or gentle, wide or narrow, and may include sand, rocks, shells, or mud. The shape of a beach depends on its material composition, wave energy, and the type of waves. Some sandy beaches have lifeguard posts, showers, and hotels. Most beachgoers visit beaches in the summer, but beaches can be visited year-round, depending on local climate.
Beaches can be wave-dominated, intermediate, or dissipative. Wave-dominated beaches have a surf zone that is typically not more than 300-500 meters wide. The surf zone may include rip channels and bars. The beach may also contain a beach berm, a large, narrow wedge of sand. The beach berm is a part of the active shoreline, and its face may contain a crest or trough. Some beaches have two or three berms. The beach berm is often formed during a storm.
Intermediate beaches are formed by a series of longer wave periods. The waves are moderately high, and there may be one or two bars that are at least 100 meters wide. These beaches are often found along the open coasts. The intermediate beaches are cut by regular rip channels. They require fine to medium sand. Some intermediate beaches may be associated with exposed bedrock. During quiet weather, a beach berm may form on the beach face.
During the winter, beaches along the mid-Atlantic coast have a higher average wave height. The stronger winter waves narrow the beach and carry sediment back offshore in bars. The beach is then subject to a process called longshore drift, which is essential to its continued existence.
During the summer, the beach faces are less steep, and the beach may have a high surf zone. During a large cyclonic storm, the waves are often accompanied by a large surge of high water. Large cyclonic storms can affect beaches on the eastern sides of continental landmasses. These large waves can pick up particles that are deposited during the summer. These particles may then form mud flats or mangrove forests. The resulting sand may be less reflective than the adjacent beach.
Beaches are generally wide and narrow, and may contain a high amount of shell content, but the beach may be relatively smooth. It is usually not a good idea to swim in a beach that is littered with trash, as the bacteria in sewage can be harmful to human health. During storms, a beach may be closed, and the sand may be removed from the beach.