These rips can appear to move down the beach aided by the prevailing wave direction. It has been documented that a strong and persistent swell begins the traveling rip process. Swells impacting one portion of the beach will temporarily enhance the rips there; however, once the swells become focused on another area the initial rips weaken while new rips strengthen in the new area. This type of rip current is strongest when the swell periods are very defined, allowing for an apparent propagation down the beach as additional sets interact with the coast.