Bambra Reef Swell Statistics, Summer: All Swell – Any Wind
The graph describes the variation of swells directed at Bambra Reef over a normal southern hemisphere summer. It is based on 5462 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the shore so we have chosen the most applicable grid node based on what we know about Bambra Reef, and at Bambra Reef the best grid node is 67 km away (42 miles).
The rose diagram describes the distribution of swell sizes and swell direction, 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 happened only 32% of the time. Green and yellow illustrate increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. In both graphs, the area of any colour is proportional to how often that size swell was forecast.
The diagram indicates that the dominant swell direction, shown by the largest spokes, was SSW, whereas the the dominant wind blows from the W. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Bambra Reef and away from the coast. We lump these in with the no surf category of the bar chart. To avoid confusion we don't show these in the rose diagram. Because wind determines whether or not waves are clean enough to surf at Bambra Reef, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical southern hemisphere summer, swells large enough to cause surfable waves at Bambra Reef run for about 39% of the time.
IMPORTANT: Beta version feature! Swell heights are open water values from NWW3. There is no attempt to model near-shore effects. Coastal wave heights will generally be less, especially if the break does not have unobstructed exposure to the open ocean.