Backdoor Surf Stats

This picture illustrates the variation of swells directed at Backdoor over a normal May, based on 3440 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind or surf right at the coastline so we have chosen the optimum grid node based on what we know about Backdoor. In this particular case the best grid node is 37 km away (23 miles). The rose diagram illustrates the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but lacks 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 occurred only 57% of the time. Green and yellow represent increasing swell sizes and red illustrates the largest swells, greater than >3m (>10ft). In each graph, the area of any colour is proportional to how frequently that size swell happens. The diagram suggests that the dominant swell direction, shown by the largest spokes, was NNW, whereas the the most common 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 Backdoor 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 graph. Because wind determines whether or not waves are good for surfing at Backdoor, you can load a different image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical May, swells large enough to cause clean enough to surf waves at Backdoor run for about 43% of the time.

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