Inlets or man-made breachways cut through the barrier beach to connect the water in the lagoon to the ocean. This cross section of a barrier beach and lagoon shows what you'd see if you cut a slice out of East Beach and Ninigret Pond. A barrier beach is constantly changing. This can happen any time of the year but because more storms happen in the winter, most beach erosion occurs then. When sand is deposited, the barrier beach grows in size and when sand is eroded from the beach, the beach gets smaller.
Wind moves grains of sand from the beach to the dunes.
The barrier beach and dunes protect the mainland from storms and hurricanes- they can be considered land's first and second lines of defense against the sea.