How We Called it: Code Red 2

Tony Butt

by on

Updated 211d ago

Way back on August 27 2011, one of the biggest ever documented swells hit Teahupoo, the famous ‘Code Red’ swell. And today, July 13 2022, another massive swell is just about to arrive. Let's take a look and see how they compare.

The 2011 swell was formed by low pressure that developed way south of Tasmania on August 22. It then went eastwards, getting stronger and bigger but remaining in the far south of the Pacific, just off the ice shelf. As it passed south of New Zealand a huge area of storm-force westerly winds developed on its northern side, which stayed there as the system continued to track east. Then, as it passed way south of Tahiti around August 24, the southwest winds on its western side increased. Wave heights in the storm centre peaked at more than 50 feet over a large area.

Forecast: Teahupoo

Our swell chart for Code Red Teahupoo...

Our swell chart for Code Red Teahupoo...

... and the spot forecast from 2011.

... and the spot forecast from 2011.

In comparison to today's swell, which was generated by two centres of low pressure that merged southeast of New Zealand on Saturday. The combined system deepened and expanded as it moved slowly eastwards. By late Sunday 10th it was just off the ice shelf about half way across the South Pacific, and had developed a huge area of storm-force winds on its northwest side. The windfield then moved NNE as the main system expanded out into the open South Pacific and pushed up against some high pressure to the west. This generated open-ocean wave heights of around 40 feet and a massive pulse of swell, the bulk of which formed towards the NNE.

Both the 2011 and 2022 swells were generated by large areas of storm-force winds associated with a low pressure system south of Tahiti. In the 2022 storm, the windspeeds weren’t quite so strong and the windfield wasn’t quite so broad as in 2011, so the wave heights initially generated in the storm centre were smaller. This suggests that the 2011 swell would have been much bigger. However, this is offset by the fact that today's storm peaked nearer to Tahiti than the 2011 one, so the wave heights won’t diminish so much as it spreads out over a wider area.

Today's Teahupoo swell.

Today's Teahupoo swell.

And the spot forecast.

And the spot forecast.

The main thrust of the Code Red swell was heading in a ENE direction. In an ocean swell, the swell components that ‘leak’ out to the sides are always smaller than the main thrust of the swell, and are smaller with greater spreading angles. The component that reached Tahiti was oblique swell that had spread out about 45 degrees. In 2022, the main thrust of the swell is heading in a NNE direction, and the spreading angle of the component that (is just about to) hit Tahiti is only about 10 degrees.

This suggests that the 2022 swell might be bigger, but it could be offset by the fact that the 2011 swell was bigger and more powerful in the storm centre itself, with larger storm wave heights over a greater area, Therefore, it would have contained more energy in the longer periods. That is very important when it comes to spots like Teahupoo that really come into their own with longer periods.

Wind in 2011.

Wind in 2011.

And 2022. There's not much in it.

And 2022. There's not much in it.

In summary, the analysis of the charts suggests that there won’t be much in it. The model predictions for Teahupoo suggest slightly smaller wave heights than the 2011 swell, with not quite such long periods. But we won’t know for sure until later today, in about a few hours in fact.

Cover shot: MSW/Corroto