A rip current is a strong surface flow of water returning outward from near the shore (not to be confused with an undertow). It is often mistakenly called a "rip tide" or "riptide", which is a flow of water out of an inland lagoon or channel during an ebb tide. Colloquially a rip current is known simply as a rip. Although rip currents would exist even without the tides, tides can make an existing rip much more dangerous (especially low tide). Typical flow is at 0.5 meters per second (1-2 feet per second), and can be as fast as 2.5 meters per second (8 feet per second). Rip currents can move to different locations on a beach break, up to tens of metres (a few hundred feet) a day. They can happen at any beach with breaking waves, including the world's oceans, seas, and large lakes such as the Great Lakes in Canada and the United States.
- Rip Current Safety (US National Weather Service)
- United States Lifesaving Association, Rip Currents
- Rip Currents - Everything a swimmer needs (pictures too) on just one page
- Rip Current Awareness (New Jersey Marine Sciences Consortium)
- Rip currents: Going with the flow (a study reveals that Rip Currents are much more complicated than was previously thought, New Scientist, 27 June 2007)