As waves travel from deep to shallow water, they will break near the shoreline. When waves break strongly in some locations and weakly in others, this can cause circulation cells which are seen as rip currents: narrow, fast-moving belts of water traveling offshore.
Rip currents are the leading surf hazard for all beach goers. They are particularly dangerous for weak or non-swimmers, but can sweep even the strongest swimmer out to sea.
Over 100 drownings due to rip currents occur every year in the United States and more than 80% of water rescues on beaches are due to rip currents.
REMEMBER: Only swim at a beach with lifeguards. The chances of drowning at a beach with lifeguards on duty are 1 in 18 million (U.S. Lifesaving Association).