Rip currents are formed by a beach's topography. Sandbars, reefs, or inshore holes can lead to the formation of a rip current.

Illustration by Mary Crooks

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  • 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.

  • Term Part of Speech Definition Encyclopedic Entry
    beach Noun

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

    Encyclopedic Entry: beach
    feeder wave Noun

    wave that contributes to a rip current.

    lake Noun

    body of water surrounded by land.

    Encyclopedic Entry: lake
    obstacle Noun

    something that slows or stops progress.

    ocean Noun

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

    Encyclopedic Entry: ocean
    pier Noun

    platform built from the shore and extending over water.

    reef Noun

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

    Encyclopedic Entry: reef
    rip current Noun

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

    Encyclopedic Entry: rip current
    sandbar Noun

    mound of sand created by water currents.

    sea Noun

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

    Encyclopedic Entry: sea
    sediment Noun

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

    Encyclopedic Entry: sediment
    stream Noun

    body of flowing fluid.

    topography Noun

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