Le Petits Dalles Surf Stats

This picture shows the combination of swells directed at Le Petits Dalles over a normal November. It is based on 3343 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 best grid node based on what we know about Le Petits Dalles. In this particular case 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 without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These occurred only 37% of the time. Green and yellow illustrate increasing swell sizes and red represents the biggest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how often that size swell was forecast. The diagram indicates that the most common swell direction, shown by the largest spokes, was WSW, 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 Le Petits Dalles and offshore. We combine these with the no surf category of the bar chart. To simplify things we don't show these in the rose plot. Because wind determines whether or not waves are clean enough to surf at Le Petits Dalles, you can load a different image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical November, swells large enough to cause surfable waves at Le Petits Dalles run for about 63% of the time.

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