North Jetty at Eureka Surf Stats

The rose diagram describes the variation of swells directed at North Jetty at Eureka through a typical June, based on 2786 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the most applicable grid node based on what we know about North Jetty at Eureka, and at North Jetty at Eureka the best grid node is 34 km away (21 miles). The rose diagram illustrates the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but 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 22% of the time. Green and yellow show increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how often that size swell was forecast. The diagram indicates that the prevailing swell direction, shown by the longest spokes, was NW (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 North Jetty at Eureka and away from the coast. We combine these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose diagram. Because wind determines whether or not waves are clean enough to surf at North Jetty at Eureka, you can select a similar diagram 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 North Jetty at Eureka run for about 78% of the time.

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