Swell period & how it affects waves
Swell period is the amount of time in seconds between 2 waves & is often categorized as short (< 10s), medium (10-14s), or long period (> 14s).
While this definition isn’t all that helpful, knowing how it affects waves at your local break is.
Why? Because a 3 ft swell at 7s, 12s, & 18s will each produce a different sized wave with varying quality.
Shorter period swells (i.e. “wind swells”) produce shorter, peakier waves & have less energy, fewer waves to a set, shorter lulls between sets, & will produce smaller waves than a longer period swell of equal height.
Longer period swells (i.e. “groundswells”) produce longer waves & have more energy, more waves to a set, longer lulls between sets, & will produce bigger waves than a shorter period swell of equal height.
Longer period swells are often preferred & result in a higher quality wave, but longer isn’t necessarily better as it depends on what works best for your local break.
For example, point breaks are a great place for longer period swells as they allow the long lines to break evenly from left to right or right to left.
Contrary to a beach break where those long lines need to be “broken up” or “refracted” in some way with well-defined sandbars or another type of bathymetric (ocean floor) interruption, which is why some beach breaks can handle long periods & others leave you with nothing but closeouts.
A 3 ft swell at 7s, 12s, & 18s will each produce a different sized wave with varying quality.
The opposite is true for shorter period swells. At a point break, a shorter period swell won’t span the full length of the point & you’ll end up with multiple sections not allowing the point to do its thing.
At a beach break though, there’s a better chance of having nice, peaky waves with fewer closeouts & less need for solid sandbars.
These are just general guidelines though & every spot handles various swell periods differently, so what’s considered the ideal period is relative to your local break (not to mention other variables).
💬 Have you noticed what periods work best for you local break?
🙏 Enjoying this series? Share the stoke & buy me a beer! 😄🍻