NW swell in Cape Town

THEORY VS REALITY: Realtime Windy shows fair swell, as seen in the Long Beach cam.

I just chatted to Piet Streicher, avid windsurfer and founder of BulkSMS.com, who had a great surf at Derde Steen yesterday as a clean long period three foot northwest swell lined up beautifully along the sandbank. With a degree in coastal engineering, Piet is an avid follower of the charts, and was instrumental in helping me set up the Wavescape Ocean Watch system back in the day.

There's been a lot of storm activity in the northern hemisphere, notably a large storm off North America in the North Atlantic. This swell has been travelling for five or six days, and has crossed the equator to reach us.

With a period of 17 seconds, group celerity (set speed) is 41km/h and wave celerity (individual waves in the group) is 82km/h. You can reverse calculate how far it has come.

The Long Beach cam indicates a clean three foot swell. With the current stiff south wind, that's about the only spot that will register the swell and be offshore at the same time. However, the surf appears to be bigger the further up the West Coast you go, which of course means some lefthand points may well also be working today.

In fact, who knows, but perhaps those spots in Namibia are going gang-busters and the locals at Skeleton Bay are laughing their heads off after getting barrelled for two days with no-one in the desert except a few black-backed jackals.