- undertow (def. 1).[1935-40]
* * *or riptideNarrow, jetlike stream of water that flows sporadically seaward for several minutes, in a direction perpendicular to a beach.The term riptide is a misnomer because the currents are in no way related to tides. Rip currents form at long coasts that are approached by wave trains that are nearly parallel to the shoreline. In shallow water, normal wave motion displaces the water small distances shoreward with each passing wave. During periods of large waves, water builds up at the beach and cannot escape as longshore currents, which require oblique wave approach. The buildup continues until water can escape by surging for several minutes through a low point in a breaker, creating an undertow that can be dangerous for swimmers.
* * *also called Riptide,narrow jetlike stream of water that flows sporadically seaward for several minutes, in a direction normal or nearly normal to a beach. Such currents are probably the cause of most ocean bathing accidents blamed on undertow. The term riptide is often used but is a misnomer, the currents being related in no way to tides.Rip currents may have velocities as great as 1 metre per second (3.3 feet per second, or 2 knots) and extend offshore from 60 to 760 m (200 to 2,500 feet). The energies of the currents may be sufficient to erode shallow channels through offshore bars, and the water may be discoloured by suspended sand. Swimmers caught in a rip current should not attempt to swim shoreward directly against the current. Instead, it is best to swim a short distance parallel to the beach to emerge from the rip current before returning to shore.Rip currents form at long coasts that are approached by wave trains oriented parallel or nearly parallel to the shoreline. In shallow water the orbital motion in normal waves and swell displaces the water particles small distances shoreward with each passing wave. This mass transport is increased with increasing wave size; and during periods of large waves, water builds up at the beach and cannot escape as longshore currents, which require oblique wave approach. The buildup of water continues until some of the water can escape by surging for several minutes through a low point in a breaker.
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Look at other dictionaries:
Rip current — Riptide redirects here. For other uses, see Riptide (disambiguation). Rip current, as seen from above. The beach is visible at the right top … Wikipedia
rip current — noun a strong surface current flowing outwards from a shore • Syn: ↑riptide • Hypernyms: ↑current, ↑stream • Part Holonyms: ↑tide * * * ˌrip ˈcurrent 7 [rip current … Useful english dictionary
Rip current — Brandungsrückstrom, auch Rippströmung oder Trecker, ist die deutsche Bezeichnung für sogenannte riptides oder genauer rip currents, die zumindest an den Meeresküsten die wichtigste Ursache für Badeunfälle sind. Grundsätzlich sind die Wellen der… … Deutsch Wikipedia
rip-current — /ˈrɪp kʌrənt/ (say rip kuruhnt) noun → rip tide … Australian English dictionary
rip current — rip (2) … Dictionary of ichthyology
rip current — noun A strong flow of surface water, away from the shore, that returns water from incoming waves Syn: rip tide, riptide, rip … Wiktionary
rip current — noun Date: 1936 a strong usually narrow surface current flowing outward from a shore that results from the return flow of waves and wind driven water … New Collegiate Dictionary
rip current — noun an intermittent strong surface current flowing seaward from the shore … English new terms dictionary
rip|tide — «RIHP TYD», noun. a strong, narrow surface current which flows rapidly away from the shore usually at a right angle to it; rip current. A riptide flows against another current, usually causing a violent disturbance … Useful english dictionary
rip-tide — /ˈrɪp taɪd / (say rip tuyd) noun a fast flowing tide such as might be associated with the formation of a rip. Also, rip current … Australian English dictionary