Statistiques de Surf de Collaroy

This picture describes the range of swells directed at Collaroy through a typical October. It is based on 3471 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 best grid node based on what we know about Collaroy. In the case of Collaroy, the best grid node is 31 km away (19 miles). The rose diagram describes the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but lacks direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These happened only 71% of the time. Green and yellow illustrate increasing swell sizes and red represents the highest 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 prevailing swell direction, shown by the largest spokes, was ENE (which was the same as the dominant wind direction). Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Collaroy 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 Collaroy, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average October, swells large enough to cause surfable waves at Collaroy run for about 10% of the time.

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