Backdoor Surf Stats

The graph describes the combination of swells directed at Backdoor 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 and surf right at the coast so we have chosen the most applicable grid node based on what we know about Backdoor, and at Backdoor the best grid node is 9 km away (6 miles). The rose diagram illustrates the distribution of swell sizes and swell direction, 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 9% of the time. Green and yellow show increasing swell sizes and red shows highest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell was forecast. The diagram implies that the most common swell direction, shown by the longest spokes, was SE, whereas the the dominant wind blows from the E. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Backdoor and offshore. We combine 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 select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. Over an average October, swells large enough to cause clean enough to surf waves at Backdoor run for about 91% of the time.

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