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Black Rock ratings
Quality on a good day: 4.0
Consistency of Surf: 3.0
Difficulty Level: 1.0

Overall: 3.0

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Surf Report Feed

Black Rock Swell Statistics, December: All Swell – Any Wind

The graph describes the variation of swells directed at Black Rock through an average December and is based upon 2953 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 most applicable grid node based on what we know about Black Rock, and at Black Rock the best grid node is 23 km away (14 miles).

The rose diagram describes the distribution of swell sizes and directions, 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 21% of the time. Green and yellow illustrate increasing swell sizes and red shows the highest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how frequently that size swell was forecast.

The diagram suggests that the prevailing swell direction, shown by the longest spokes, was WSW (which was the same as the dominant wind direction). Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Black Rock and away from the coast. We combine these 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 Black Rock, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. In a typical December, swells large enough to cause clean enough to surf waves at Black Rock run for about 51% 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.