Vivonne Bay Surf Stats

The figure illustrates the variation of swells directed at Vivonne Bay through a typical May. It is based on 3440 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the shore so we have chosen the most applicable grid node based on what we know about Vivonne Bay. In the case of Vivonne Bay, the best grid node is 59 km away (37 miles). The rose diagram shows the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but lacks direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These occurred only 0.8% of the time. Green and yellow represent increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In both graphs, the area of any colour is proportional to how frequently that size swell occurs. The diagram suggests that the dominant swell direction, shown by the largest spokes, was SW, whereas the the most common wind blows from the WNW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Vivonne Bay and out to sea. We group these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose graph. Because wind determines whether or not waves are clean enough to surf at Vivonne Bay, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average May, swells large enough to cause surfable waves at Vivonne Bay run for about 30% of the time.

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