Three Rocks Surf Stats

The figure describes the combination of swells directed at Three Rocks through a typical April and is based upon 3360 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and surf right at the coast so we have chosen the most applicable grid node based on what we know about Three Rocks. In the case of Three Rocks, the best grid node is 24 km away (15 miles). The rose diagram describes the distribution of swell directions and swell sizes, 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 99% of the time. Green and yellow represent increasing swell sizes and red shows the highest swells, greater than >3m (>10ft). In both graphs, 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 NNW, whereas the the dominant wind blows from the E. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Three Rocks and out to sea. We combine these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose plot. Because wind determines whether or not waves are good for surfing at Three Rocks, you can select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. Over an average April, swells large enough to cause clean enough to surf waves at Three Rocks run for about 1.0% of the time.

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