Statistiques de Surf de Derrs

The figure illustrates the variation of swells directed at Derrs over a normal June and is based upon 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 Derrs. In the case of Derrs, the best grid node is 21 km away (13 miles). The rose diagram shows the distribution of swell directions and swell sizes, 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 occurred only 1.2% of the time. Green and yellow show increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how frequently that size swell happens. The diagram suggests that the dominant swell direction, shown by the biggest spokes, was WSW, whereas the the most common wind blows from the ENE. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Derrs and out to sea. We lump these in with the no surf category of the bar chart. To simplify things we don't show these in the rose graph. Because wind determines whether or not waves are clean enough to surf at Derrs, you can select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical June, swells large enough to cause surfable waves at Derrs run for about 99% of the time.

read more