Avalanche Swell Statistics, Março: 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 March. It is based on 2220 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 show increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how frequently that size swell was forecast.
The diagram suggests that the dominant swell direction, shown by the largest spokes, was NNW, whereas the the most common wind blows from the ENE. 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 43% of the time, equivalent to 13 days. Open water swells exceeding >3m (>10ft) only occur 1.7% of the time in a typical March, equivalent to just one day but 21% of the time we expect swell in the range 2-3m (6.5-10ft) 21%, equivalent to (7 days). Taking into account the ratio of these swells that coincided with forecast offshore winds, and given the fact that Avalanche is exposed to open water swells, we estimate that clean surf can be found at Avalanche about 43% of the time and that surf is messed up by onshore wind 26% of the time. This is means that we expect 21 days with waves in a typical March, of which 13 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.