Itaipu Surf Stats

The graph shows the range of swells directed at Itaipu through a typical June. It is based on 3506 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 best grid node based on what we know about Itaipu. In this particular case the best grid node is 5 km away (3 miles). The rose diagram illustrates the distribution of swell sizes and directions, while the graph at the bottom shows the same thing without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These happened only 36% of the time. Green and yellow show increasing swell sizes and red represents the biggest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how often that size swell occurs. The diagram indicates that the most common swell direction, shown by the longest spokes, was S, whereas the the prevailing wind blows from the NE. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Itaipu 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 diagram. Because wind determines whether or not waves are clean enough to surf at Itaipu, 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 June, swells large enough to cause surfable waves at Itaipu run for about 64% of the time.

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