Colac Bay Surf Stats

The figure describes the variation of swells directed at Colac Bay through an average November. It is based on 3347 NWW3 model predictions since 2006 (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 Colac Bay. In the case of Colac Bay, the best grid node is 77 km away (48 miles). The rose diagram illustrates the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing 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 occurred only 65% of the time. Green and yellow show increasing swell sizes and red represents the 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 SW, whereas the the dominant wind blows from the WNW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Colac Bay and offshore. We combine these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose plot. Because wind determines whether or not waves are surfable at Colac Bay, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical November, swells large enough to cause good for surfing waves at Colac Bay run for about 35% of the time.

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