Slaughterhouse Swell Statistics, All Year: All Swell – Any Wind
This chart describes the range of swells directed at Slaughterhouse over a normal year, based on 26892 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the shore so we have chosen the optimum grid node based on what we know about Slaughterhouse. In the case of Slaughterhouse, the best grid node is 15 km away (9 miles).
The rose diagram describes the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but lacks direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These occurred only 46% of the time. Green and yellow show 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 commonly that size swell was forecast.
The diagram implies that the dominant swell direction, shown by the longest spokes, was N, whereas the the dominant wind blows from the E. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Slaughterhouse and away from the coast. We combine these with the no surf category of the bar chart. To simplify things we don't show these in the rose plot. Because wind determines whether or not waves are surfable at Slaughterhouse, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical year, swells large enough to cause good for surfing waves at Slaughterhouse run for about 54% 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.