Statistiques de Surf de Dirk Hartog Island

The graph illustrates the variation of swells directed at Dirk Hartog Island through a typical September, based on 2880 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the shore so we have chosen the optimum grid node based on what we know about Dirk Hartog Island, and at Dirk Hartog Island the best grid node is 28 km away (17 miles). The rose diagram shows the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These occurred only 0.1% of the time. Green and yellow illustrate increasing swell sizes and red illustrates the largest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell happens. The diagram indicates that the dominant swell direction, shown by the biggest spokes, was SW, whereas the the most common wind blows from the S. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Dirk Hartog Island and out to sea. We group these with the no surf category of the bar chart. To simplify things we don't show these in the rose diagram. Because wind determines whether or not waves are surfable at Dirk Hartog Island, you can view an alternative image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. Over an average September, swells large enough to cause good for surfing waves at Dirk Hartog Island run for about 99% of the time.

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