Statistiques de Surf de Grande Trait

The graph illustrates the combination of swells directed at Grande Trait through a typical September, based on 3360 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the shore so we have chosen the optimum grid node based on what we know about Grande Trait. In this particular case the best grid node is 30 km away (19 miles). The rose diagram describes the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but without direction information. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These happened only 23% of the time. Green and yellow represent 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 commonly that size swell happens. The diagram implies that the most common swell direction, shown by the longest spokes, was W, whereas the the most common wind blows from the NNW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Grande Trait and away from the coast. We lump these in with the no surf category of the bar chart. To simplify things we don't show these in the rose plot. Because wind determines whether or not waves are clean enough to surf at Grande Trait, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. Over an average September, swells large enough to cause surfable waves at Grande Trait run for about 77% of the time.

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