Kanaha Swell Statistics, April: Surf with Light or Offshore Winds
This image shows only the swells directed at Kanaha that coincided with light winds or offshore conditions over a normal April. It is based on 2160 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. Green and yellow illustrate 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 often that size swell occurs.
The diagram indicates that the dominant swell direction, shown by the longest spokes, was NNE, whereas the the most common wind blows from the E. 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 41% of the time, equivalent to 12 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal April but 16% of the time we expect swell in the range 2-3m (6.5-10ft) 16%, equivalent to (5 days). Taking into account the proportion of these swells that coincided with forecast offshore winds we calculate that clean surf can be found at Kanaha about 41% of the time and that surf is spoilt by onshore wind 19% of the time. This is means that we expect 18 days with waves in a typical April, of which 12 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.