Columbia St Surf Stats

This image shows the variation of swells directed at Columbia St through an average April, based on 3360 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the optimum grid node based on what we know about Columbia St. In this particular case the best grid node is 35 km away (22 miles). The rose diagram shows the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but lacks direction information. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These were forecast only 72% of the time. Green and yellow show increasing swell sizes and red represents biggest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how frequently that size swell happens. The diagram suggests that the prevailing swell direction, shown by the largest spokes, was ENE, whereas the the prevailing wind blows from the SW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Columbia St and offshore. We combine these with the no surf category of the bar chart. To keep it simple we don't show these in the rose graph. Because wind determines whether or not waves are surfable at Columbia St, you can load a different image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. In a typical April, swells large enough to cause good for surfing waves at Columbia St run for about 9% of the time.

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