High in the South Hemisphere’s atmosphere warm air from an ex-tropical cyclone is pushed south. When this warm tropical mass meets the cold Antarctic air the contrast between the two, super charges a normal low pressure storm. The lower the pressure, the stronger the winds. The stronger the winds, the more energy in the waves. This supercharged low pressure storm also alters the normal east-to-west track of the waves. This track is tilted south-north. That is, towards Tahiti. These powerful swell fan upwards and travel thousands of kilometres across the deep South Pacific. There’s no continental shelves to distort their speed or uniformity. Nor any sloping sandy ocean floors to drag 'em down. 

Kelly capitalising on the bold forces which conspired to create this arch in the ocean. Photo: WSL/Scholtz

Eventually this swell bears down on Tahiti-Iti, and the tip of it, Teahupoo. Here the ocean floor finally starts to change depth, but only very close to the island. Five kilometres offshore the water depth is still a mile deep. 500 metres offshore it is still 300 metres deep. The waves are unaware they are soon about to crash into a shallow coral reef. 

Finally the ocean floor steepens. Now with normal beachbreaks, the ocean floor steepness ratio is around 1:40 (climbing one metre vertically for every 40 horizontal). In the most hollow of waves that ratio can drop as lows as 1:10. 50 metres out from Chopes, the ratio is an incredible 1:1 Only in that last 50 metres does it correct itself to 1:3. At such ratios the wave don’t have time to stand up and break like normal. They simply “shoal” or surge over the reef. 

Teahupoo's unique bathymetry means it's almost uncatchable at a certain size. WSL/ Scholtz

Now usually this surge would be impossible to catch as it would simply fold over itself, expended of its energy with the spent water ending up in the lagoon. However Teahuppo has a channel next to the reef, which is 50 metres deep. This allows the wave to refract, or bend, towards the shallow zone. This horseshoe effect creates an opening and exit for the wave. It also makes Chopes one of the best barrels in the world. 

Of course a surfer, in a singlet, surfing in the Tahiti Pro Teahupoo is probably unaware of Antarctic cold air, south-north tracks and ocean floor steepness ratios. He’s probably just trying to stay calm, or stop Gabriel Medina from sneaking the inside. Yet when this waves comes, he has to catch the surge. 

When he does cameras film the action and microphones capture Pottz talking about the board looking good under his feet. That video and audio footage is fed into a computer using the appropriate interface hardware. Software turns that footage into a format suitable for live streaming. The encoded output is then broken up into little bits known as packets and then sent through underwater fibre optic cables. This is what’s known as the internet. The packets are reassembled in order by the WSL’s streaming servers and rebroadcast, in real time, to multiple viewers by a website link. Assuming Facebook hasn’t fucked you over. You then click on that link and watch someone score a 4.75. It’s been a long journey from that warm air to that average score, and, if you’ve come this far, an even longer read.