A rip current is a strong flow of water running from a beach back to the open ocean, sea, or lake.

Rip currents are formed by a beach's topography. Rip currents can occur in areas with hard-bottom (rocky) or soft-bottom (sand or silt) beach topography.

Rip currents can form in a gap between sandbars, piers, or parts of a reef. Such underwater obstacles block waves from washing directly back to sea. The water from these waves, called feeder waves, runs along the shore until it finds an opening around the obstacle.

The stream of water, now a rip current, rushes to the opening, just like water down a drain. A rip current flows more quickly than the water on either side of it, and may stir up sediment from the beach. This sometimes makes rip currents easy to spot as dark or muddy lines running from the beach out toward the ocean. Rip currents are also usually more calm-looking than the surrounding water. Once past the obstacle (between the sandbars or piers), a rip current loses pressure and stops flowing.

Noun

narrow strip of land that lies along a body of water.

feeder wave
Noun

wave that contributes to a rip current.

Noun

body of water surrounded by land.

obstacle
Noun

something that slows or stops progress.

Noun

large body of salt water that covers most of the Earth.

pier
Noun

platform built from the shore and extending over water.

Noun

a ridge of rocks, coral, or sand rising from the ocean floor all the way to or near the ocean's surface.

Noun

a strong flow of water running from the shore to the open ocean, sea, or lake.

sandbar
Noun

mound of sand created by water currents.

Noun

large part of the ocean enclosed or partly enclosed by land.

Noun

solid material transported and deposited by water, ice, and wind.

stream
Noun

body of flowing fluid.

topography
Noun

study of the shape of the surface features of an area.