Rip Currents

August 01, 2016

Rip%20Flow

Periodic%20Rips

Photographer: Dave Lynch
Summary Author: Dave Lynch

Rip currents are strong, narrow currents in the surf zone flowing outward from sandy beaches. They scour the bottom, creating deeper areas where there's little or no surf and appear relatively calm. The perfect place to enter the ocean, right? Wrong! Rips can quickly carry the hapless swimmer offshore. Swimming directly back toward shore is seldom possible and if the swimmer panics, they could be in trouble. The best approach is to swim parallel to the shore and out of the rip.

These treacherous currents form when waves on either side of the rip run up on the beach then drain back to the ocean in the rip. They can also look differently depending on conditions. Sometimes they're dark and lack breaking waves. Other times they appear as white rivers of foam carried outward beyond the breakers. Rips are easy to see from the air or elevated platforms like lifeguard shacks.

Most sandy beaches have rips at one time or another, especially when the waves are large. Their prevalence depends on wave height and shape of the bottom. Bottom shape can vary depending on whether the beach is accumulating sand or losing it. Rips also tend to form in periodic rows as they scallop the sand at the edge of the surf. The first picture shown here is a Google Earth image of well-defined rip currents near Betty’s Bay, South Africa. The second is a Google Earth image showing nearly equally-spaced rips near Blue Horizon Bay, South Africa.