Tidal race


View to Lunga from Scarba, across Scotland's "Grey Dog" tidal race

Tidal race or tidal rapid is a natural occurrence whereby a fast-moving tide passes through a constriction, resulting in the formation of waves, eddies and hazardous currents. The constriction can be a passage where the sides narrow, for example the Gulf of Corryvreckan and the Saltstraumen maelstrom, or an underwater obstruction (a reef or rising seabed), such as is found at the Portland Race in the United Kingdom.

In extreme cases, such as Skookumchuck Narrows in British Columbia, through which tides can travel at more than 17 knots, very large whirlpools develop, which can be extremely hazardous to navigation.

Notable tidal races

See also

  • Gut (coastal geography) – Narrow coastal body of water, a channel or strait, usually one that is subject to strong tidal currents, or a small creek
  • Rip current – Narrow current of water that moves directly away from the shore, cutting through the lines of breaking waves
  • Tidal bore – A water wave traveling upstream a river or narrow bay because of an incoming tide


  1. ^ "Nature"
  2. ^ The-Bitches.co.uk
  3. ^ UK Riversguidebook
  4. ^ CanoeWales Archived 2014-09-11 at the Wayback Machine
  5. ^ "Bitches and Tides"