Chapter 12 - Rip Currents

Abstract

Rip currents are strong, narrow seaward flows found on many global beaches where waves break across a surf zone. They represent a major hazard to bathers contributing to hundreds of drownings and tens of thousands of rescues annually. Most rip currents occupy deep channels situated between shallow sandbars or against structures. Rip current flow is unsteady with mean velocities typically on the order of 0.3–0.5m/s, but with instantaneous flows in excess of 2m/s. Recent field, laboratory, and numerical modeling studies have challenged traditional views of rip current behavior and, in combination with lifeguard reports, have helped improve understanding of the physical environmental factors leading to maximum rip current risk. Although collaborative research efforts between rip current scientists and beach safety organizations are increasing, significant challenges remain for improving and communicating education and awareness of the rip current hazard to the beachgoing public.