Avalanche Swell Statistics, January: All Swell – Any Wind
The graph describes the range of swells directed at Avalanche over a normal January and is based upon 2372 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the shore so we have chosen the best grid node based on what we know about Avalanche, and at Avalanche the best grid node is 39 km away (24 miles).
The rose diagram describes the distribution of swell sizes and directions, while the graph at the bottom shows the same thing without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These were forecast only 1.4% of the time. Green and yellow illustrate increasing swell sizes and red illustrates highest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how frequently that size swell was forecast.
The diagram suggests that the most common swell direction, shown by the biggest spokes, was W, whereas the the dominant wind blows from the SSE. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Avalanche 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 diagram. Because wind determines whether or not waves are surfable at Avalanche, you can view an alternative image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical January, swells large enough to cause good for surfing waves at Avalanche run for about 99% 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.