Avalanche Swell Statistics, Outubro: Surf with Light or Offshore Winds
This image shows only the swells directed at Avalanche that coincided with light winds or offshore conditions through a typical October. It is based on 2480 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. Green and yellow illustrate increasing swell sizes and red illustrates the highest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how frequently that size swell occurs.
The diagram suggests that the prevailing swell direction, shown by the largest spokes, was W, whereas the the dominant wind blows from the WNW. The chart at the bottom shows the same thing but without direction information. For example, swells larger than 1.5 feet (0.5m) coincided with good wind conditions 24% of the time, equivalent to 7 days. Open water swells exceeding >3m (>10ft) only happen 1.9% of the time in a typical October, equivalent to just one day but 11% of the time we expect swell in the range 2-3m (6.5-10ft) 11%, equivalent to (3 days). Taking into account the proportion of these swells that coincided with forecast offshore winds, and given the fact that Avalanche is exposed to open water swells, we think that that clean surf can be found at Avalanche about 24% of the time and that surf is spoilt by onshore wind 74% of the time. This is means that we expect 30 days with waves in a typical October, of which 7 days should be clean enough to surf.
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.