Big Rock Surf Stats

The rose diagram shows the combination of swells directed at Big Rock through an average May, based on 3440 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the coast so we have chosen the best grid node based on what we know about Big Rock, and at Big Rock the best grid node is 28 km away (17 miles). The rose diagram describes the distribution of swell directions and swell sizes, 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 72% of the time. Green and yellow represent increasing swell sizes and red shows biggest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell was forecast. The diagram indicates that the prevailing swell direction, shown by the biggest spokes, was WSW (which was the same as the prevailing wind direction). Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Big Rock and away from the coast. We combine these with the no surf category of the bar chart. To keep it simple we don't show these in the rose plot. Because wind determines whether or not waves are clean enough to surf at Big Rock, you can view an alternative image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical May, swells large enough to cause surfable waves at Big Rock run for about 28% of the time.

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