Combining Swells Issue

Some feedback on the new forecast highlights cases like this where the basic overview is dramatically different – it’s worth explaining because it highlights a considerable issue with the old layout that helps explain why we’ve made the change. You can see below an image showing the differences for Cape Town this week:

On the face of it a 50% larger call on the old forecast than the new one. In fact the situation is pretty simple – in both cases the model data is the same but the difference is the way we interpret the fact that there are actually two swells running: A solid SW ground swell and another large, low period SE wind swell. Both versions of our website show this information but the old layout also included this view of the combination of both swells, where the new website ONLY shows the dominant swell heading in the right direction for the beach by default – or all swells if you click the blue ‘multiple swells’ button in the header.

Clicking this you’ll see:

Now you can see both swells you’ll understand why showing both combined is a bad call. That 2m@14 SW swell will be making waves on all the west facing beaches, where the windswell won’t be offering a thing. On the flip side our Muizenberg forecast is showing the exact opposite. That incoming wind swell will be making some reasonable sized blown out surf with that strong onshore, while nothing of that SW will find it’s way into shelter. It’s long been an issue for us that surfers weren’t finding this vital information and the new layout is a step to addressing that. Other forecast sites, Windguru for example, only show this combination of swells and while it’s very accurate if you’re offshore (the swell affecting a boat rounding the Cape of Good Hope will be a combination of these two)¬†for surfers you need to be able to break the swells out to figure out an accurate call for your local beach.