No 34: Giant Swell Assembly Line

A huge fetch the size of eight countries

By early Saturday, the monster extended from Antarctica to Cape Point, one continuous conveyor belt of ever-building mayhem.

Looking at the virulent red blob in the charts that indicated wind speed, and the ferocity of the wind inside the storm, it brought to mind the insane ravings of King Lear as he spirals into madness on the heath: "Blow, winds, and crack your cheeks! rage! blow!; You cataracts and hurricanoes, spout; Till you have drench’d our steeples, drown’d the cocks!

Well, this storm did that and then some.

As a surfing forecaster, I have never seen a storm so monstrously bloated, so hideously malformed. The chunk of ocean blown asunder by Westerly gales is larger than eight African countries combined. Picture an area the size of South Africa, Namibia, Botswana, Zimbabwe, Mozambique, Zambia, Swaziland, and Lesotho. That is a distance of 4.6 million square kilometres.  

If you had to draw a line from the tail of this behemoth, 100 miles off the Antarctic ice shelf, to the tip of its snarling snout, which ferociously snapped at Cape Point, you would draw for 2,000 nautical miles. That is 3,700 km of howling gale, part of which is an 800 km stretch that this morning packs winds of hurricane force to 64 knots. And all this pointed straight at us.

No wonder surfers gibbered quietly while dusting their big wave 'rhino' chasers.

Forming early Friday, the storm rammed into the underbelly of Africa on Saturday, striking a savage blow to the coast between Cape Columbine and Cape Agulhas, spreading towards Port Elizabeth on Sunday in the form of strong gales of 80kts in places. Swell in Cape Town on Sunday reached 40 feet or more, but seldom do you see such a contorted morass of mountainous mayhem, such a wild and crazy mixture of sizes and shapes in the sea.

By 8am Sunday, the mega-low pressure system reached 940 millibars of pressure at its epicentre 1200 nautical miles (2220km) south of Cape Town. The storm is so far away, and yet here we sat smack bang in the thick of the weather formed by it.

Two of the main southern promontories between Cape Town and Port Elizabeth, namely Cape Point and Cape Agulhas, were Sunday positioned in the middle of a gigantic wave assembly line. Usually, a groundswell has some distance to propagate away from the storm that created it. There is time for the swell to glide through the ocean from the generating point to the shore where it will break.

Not this time. Giant swells are pouring off the conveyor belt and smashing straight into us before the last widget was applied, before the top-heavy swell packages could be bottled, labelled and stacked into the delivery van. Talk about bearing the brunt of Neptune’s full arsenal.

On Sunday morning, tow crews might have expected to patrol the coast around Dungeons, but they would have had to wait for the gales to ease before they could consider scooting down a few eight-storey buildings at Tafelberg Reef.

Meanwhile, the point breaks in the Southern and Eastern Cape are becoming giant, with all but the most extreme-angled bays completely out of control at 15 feet, getting even bigger on Monday into Tuesday, as an almost unheard-of 20 second swell surges up the coast. This deep energy swell – with gaps of 20 seconds between waves – is the result of today’s hurricane-force peak in the storm. It is close to the most powerful possible from a wind-generated source, and the first time I have ever seen a swell with that interval in South Africa.

To cap this, consider that four of the biggest swells Cape Town has seen in the last eight years came within 17 days of each other, between 19 August and 5 September, straddling the transition between winter and spring.

A monster storm hurled the Ikan Tanda aground at Misty Cliffs on 5 September 2001. A giant swell pushed the Sealand Express ashore on 19 August 2003. False Bay was hammered by a huge swell on 27 August 2005.

And now this one, peaking on the eve of spring, 31 August 2008.