Arica Swell Statistics, Spring: Surf with Light or Offshore Winds
This image shows only the swells directed at Arica that coincided with light winds or offshore conditions through a typical southern hemisphere spring and is based upon 7252 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. Green and yellow show increasing swell sizes and red represents the largest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how commonly that size swell occurs.
The diagram implies that the dominant swell direction, shown by the largest spokes, was SW, whereas the the most common wind blows from the S. 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 3% of the time, equivalent to 3 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal southern hemisphere spring but 2% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 2%, equivalent to (2 days). Taking into account the proportion of these swells that coincided with expected offshore winds, and given the fact that Arica is exposed to open water swells, we estimate that clean surf can be found at Arica about 3% of the time and that surf is messed up by onshore wind 96% of the time. This is means that we expect 90 days with waves in a typical southern hemisphere spring, of which 3 days should be surfable.
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.