Rip currents occur where a longshore current meets a physical barrier such as a peninsula, headland, long groin, harbor breakwater, nearshore reef or shoal and is deflected lakeward. Rip currents occur in fresh water, not just saltwater. These currents also occur along an open beach where there is less resistance to lakeward flow, such as places where the breaking waves are lower, or where there is a gap or trough in the nearshore sand bars.
Once a rip current is established, it can scour its own channel through the bars and be a relatively stable current until wave conditions change. Rip currents are usually narrow. Swimmers can escape them by swimming perpendicular to the flow (parallel to shore) a short distance.