June 2016 (ROTM#90) North Cronulla Beach, Sydney, Australia

'Cronulla' Beach is the longest of Sydney's southern beaches although it is actually given a bunch of different names depending on what part of the beach you're on (Cronulla, North Cronulla, Wanda, Elouera, Greenhills). It's also got a long history of sand mining, erosion and controversial seawalls. Despite all that, it's a great beach....and a very rippy one. Normally you get a bunch of channelised rip currents along the beach every 150 m or so, but this picture is a little different. 

 You should notice that in front of the wider part of the sandy beach there's a few dark green gaps in the surf, with some sand plumes and churning, turbulent water heading offshore. Those are rips. Look more closely and you can see this spiralling vortex quite a ways offshore, the remnants of what we call a 'rip pulse'. Rip pulses are sudden accelerations of the rip flow that may last for a minute or so and result in the rip flowing way offshore.

 You should also notice that the waves are big and clean with a long wavelength and that they are approaching the shoreline straight on. This type of swell wave is associated with 'sets' of larger waves. When the sets break, the rips tend to pulse. Good conditions for surfing, but not so good for swimming. Thanks to Beth Noel of Sutherland Shire Council for the pic. 

Look for the hidden swirl. Amazing.