Avalanche Surf Stats

The graph shows the variation of swells directed at Avalanche over a normal September and is based upon 3360 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coast so we have chosen the optimum grid node based on what we know about Avalanche. In this particular case the best grid node is 41 km away (25 miles). The rose diagram describes the distribution of swell directions and swell sizes, 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 65% of the time. Green and yellow illustrate increasing swell sizes and red shows the biggest swells, greater than >3m (>10ft). In each graph, the area of any colour is proportional to how often that size swell happens. The diagram indicates that the most common swell direction, shown by the longest spokes, was NNW, whereas the the prevailing wind blows from the ENE. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Avalanche and offshore. We lump these in with the no surf category of the bar chart. To keep it simple we don't show these in the rose diagram. Because wind determines whether or not waves are good for surfing at Avalanche, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical September, swells large enough to cause clean enough to surf waves at Avalanche run for about 35% of the time.

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