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Grand Rivere ratings
Quality on a good day: 3.0
Consistency of Surf: 2.0
Difficulty Level: 2.0
Wind and Kite Surfing: 4.0
Crowds: 3.0

Overall: 3.2

See all 18 ratings

Based on 2 votes. Vote


Surf Report Feed

Grand Rivere Swell Statistics, Autumn: All Swell – Any Wind

The figure shows the range of swells directed at Grand Rivere over a normal northern hemisphere autumn and is based upon 8724 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coastline so we have chosen the most applicable grid node based on what we know about Grand Rivere. In this particular case the best grid node is 20 km away (12 miles).

The rose diagram describes the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing without direction information. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These happened only 26% of the time. Green and yellow show increasing swell sizes and red illustrates biggest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how commonly that size swell was forecast.

The diagram implies that the dominant swell direction, shown by the biggest spokes, was NE, whereas the the prevailing wind blows from the E. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Grand Rivere and away from the coast. We group these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose graph. Because wind determines whether or not waves are surfable at Grand Rivere, 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 northern hemisphere autumn, swells large enough to cause good for surfing waves at Grand Rivere run for about -1% of the time.

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.