Rip currents are caused by
differences in density and temperature,
breaks or changes in longshore currents,
the moon's gravitational pull on earth's water,
the force of impact from an external object.

Rip currents are caused by breaks or changes in long shore currents. They can occur along any coastline that features breaking waves. As waves travel from deep to shallow water, they eventually break near the shoreline. As flow in waves break, they generate currents that flow in both the offshore (away from the coast) and the alongshore directions. Currents flowing away from the coast are called rip currents. Rip currents may extend 61 to 762 m (200 to 2,500ft) lengthwise , but they are typically less than 9 m (30 feet) wide and they may move at 5 miles per hour (8 kph) or faster.