September 2012 (ROTM#45) Bar Beach, NSW, Australia

When waves are big and messy, rip currents can become equally big and messy. While waves can change quickly, sand bars and channels can’t and fixed rips, which have been sitting comfortably in deeper channels between sand bars suddenly start to become unstable. They aren’t particularly good at accommodating all the extra water brought in by the larger waves so the rip flow isn’t as constrained and literally starts ‘popping out’ of the channel and the rip flow becomes wider, more unsteady and unstable, and harder to see.

This rip current at Bar Beach (in Newcastle, NSW) is a good example of this. Sometimes the rip flow slows down as the rip expands in width, other times it pulses quite strongly.  These types of rips are often called ‘flash’ rips because they vary so much and are unpredictable. While you can still pick out the darker area between breaking waves that is the rip, there’s also a lot of turbulent whitewater, choppier surface conditions, and clouds of suspended sand. We don’t have a good understanding of flash rips and there’s a bit of a debate about what they actually are and how we define them, but they tend to occur more with strong onshore wind waves and storms and pulse a lot. We assume they flow faster, because the waves are larger, but no-one’s really been able to measure them so we’re not sure.

When it’s messy, it’s best to swim between the flags (in Australia) or where the lifeguards are. Better yet, talk to a lifeguard about the conditions.

Always harder to spot rips in messy wave conditions