Periodicty and Swell Size Equal How Big a Wave?

 

Periodicity and Swell Size Equal How Big a Wave?

 

The simple rules of periodicity and swell size... albeit I am a rank amateur here! But to quote the experts, in this example:

The longer the swell period, the more water gets pushed upward. A 3-foot wave with a 10-second swell period may only grow to be a 4-foot breaking wave, while a 3-foot wave with a 20-second swell period can jack up to be a 15-foot breaking wave given the right ocean floor bathymetry.

In one instance we have two potential examples on certain dates. The angle of the swells' progress should be clear of Galapagos shadowing. So... we will just have to wait and see. Bathymetry is another factor but the water is deep out there so there should not be much drag from the high periodicity in contrast to the East Coast's continental shelf. The coastal angle in relation to the swell direction is another factor but we are not far off here when speaking of a single gradient, not multiples (e.g., NNW to WNW vs NNW to NW).

If the tide differentials are not great on days of swell arrival then going out deep or open ocean is not a safety factor, but with high tide differentials what out with all that water moving around. Later in the month when the tides move to the extremes I would err on staying on the inside riding the reforms rather than venturing out into the Beast... not to mention an outgoing tide combined with a 20mph Papagayo wind blowing! If you lost your mat it would be gone, gone, gone!!!

Here is a general table:

 

This table will help you estimate how big the waves will be based on the deep water swell height and period.
It is only a general guide based on a mathematical formula- every surf spot will take different heights and periods differently.
Reference: Airy wave theory and breaker height prediction, Komar & Gaughan. 1972

To quote swell matrix, "While this may seem like a disadvantage at first, it has several benefits for surfers. Every surfer knows:

• Some surf spots are bigger / better than others on a given day
• Tides make a huge difference on surf height and quality
• Wave period and direction are key factors in a spot going off
• Forecasts are never exactly right."