Umzumbe Surf Stats

This chart illustrates the variation of swells directed at Umzumbe over a normal November. It is based on 3347 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the optimum grid node based on what we know about Umzumbe, and at Umzumbe the best grid node is 33 km away (21 miles). The rose diagram illustrates the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These were forecast only 53% of the time. Green and yellow illustrate increasing swell sizes and red represents largest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how commonly that size swell occurs. The diagram implies that the prevailing swell direction, shown by the largest spokes, was SSW, whereas the the most common wind blows from the ESE. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Umzumbe and offshore. We lump these in with the no surf category of the bar chart. To keep it simple we don't show these in the rose graph. Because wind determines whether or not waves are clean enough to surf at Umzumbe, you can view an alternative image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical November, swells large enough to cause surfable waves at Umzumbe run for about 46% of the time.

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