A question regarding swell. - Kayak Fishing Adventures on Big Water’s Edge

Cbad Mike · 12-13-2014, 10:32 AM

When swell is measured for height how is it measured???
For example, a 4 foot swell. Would it be 4 ft measured from the median line? (where the water would be with zero swell)
Or is a 4 ft swell measured from the bottom of the swell up to the top of it???
Mike

YakDout · 12-13-2014, 10:49 AM

I was going to guess and say it was the average water line, like your first guess. But I looked it up and I was wrong. Swell is just a word for open water wave height, and it is all measured peak to trough

ImageUploadedByTapatalk1418500176.556637.jpg

jorluivil · 12-13-2014, 12:03 PM

Quote:

Originally Posted by Cbad Mike

When swell is measured for height how is it measured???
Mike

How it it measured?

Seriously?

No, seriously?

C'mon man, really?

Its measured with one of these

Dannowar · 12-13-2014, 12:04 PM

The buoys record the data as the swells rise, so does the buoy. That being said, the buoys are usually offshore and almost all beaches take a certain swell in a certain way.

Cbad Mike · 12-13-2014, 12:12 PM

Thanks Brandon...
That explains it.

Cbad Mike · 12-13-2014, 12:19 PM

Thanks Jorge for the swell reply.

jorluivil · 12-13-2014, 12:21 PM

Quote:

Originally Posted by Cbad Mike

Thanks Jorge for the swell reply.

Dude!

Seriously?

You're my Homie

I'm always there for my Homies

Cbad Mike · 12-13-2014, 12:27 PM

Quote:

Originally Posted by jorluivil

Dude!

Seriously?

You're my Homie

I'm always there for my Homies

surfisher · 12-13-2014, 12:48 PM

Others already mentioned the right answer, but it may be worth mentioning the bouys may read 3-4ft swells but at the beach it could be a bit bigger than that. Just something I've noticed as a surfer.

chris138 · 12-13-2014, 01:40 PM

Depends on where you are... Hawaiians will measure from the median to peak. So 4' Hawaiian is actually 8' here. What you're noticing is the discrepancy between swell height and wave height, which has everything to do with bathymetry and wave period. Swell is measured trough to peak. A 4' swell can easily make a 10' (face) wave if it is long period swell hitting a deep water reef. Conversely, a 4' swell with mid to short period hitting a shallow sandbar may only create a 3' face wave because the energy is dissipated by the bathymetry of the shoreline. A three foot swell at 20 second interval can make a big freaking wave if there is an underwater canyon funneling the swell, such as at the shores launch or blacks.

12-13-2014, 12:04 PM	#4
Dannowar Senior Member Join Date: Aug 2012 Posts: 1,823	The buoys record the data as the swells rise, so does the buoy. That being said, the buoys are usually offshore and almost all beaches take a certain swell in a certain way. __________________ "Beware the lollipop of mediocrity; lick it once and you’ll suck forever." — Brian Wilson

12-13-2014, 12:12 PM	#5
Cbad Mike Senior Member Join Date: Apr 2012 Location: Carlsbad Ca. Posts: 1,206	Thanks Brandon... That explains it. __________________ [SIGPIC]

12-13-2014, 12:19 PM	#6
Cbad Mike Senior Member Join Date: Apr 2012 Location: Carlsbad Ca. Posts: 1,206	Thanks Jorge for the swell reply. __________________ [SIGPIC]

12-13-2014, 10:49 AM	#2
YakDout Brandon Join Date: Jul 2011 Location: San Diego Posts: 2,345	I was going to guess and say it was the average water line, like your first guess. But I looked it up and I was wrong. Swell is just a word for open water wave height, and it is all measured peak to trough ImageUploadedByTapatalk1418500176.556637.jpg

12-13-2014, 12:48 PM	#9
surfisher Senior Member Join Date: Nov 2014 Location: Carlsbad Posts: 388	Others already mentioned the right answer, but it may be worth mentioning the bouys may read 3-4ft swells but at the beach it could be a bit bigger than that. Just something I've noticed as a surfer.

12-13-2014, 01:40 PM	#10
chris138 donkey roper Join Date: Apr 2009 Location: Pacific Beach Posts: 968	Depends on where you are... Hawaiians will measure from the median to peak. So 4' Hawaiian is actually 8' here. What you're noticing is the discrepancy between swell height and wave height, which has everything to do with bathymetry and wave period. Swell is measured trough to peak. A 4' swell can easily make a 10' (face) wave if it is long period swell hitting a deep water reef. Conversely, a 4' swell with mid to short period hitting a shallow sandbar may only create a 3' face wave because the energy is dissipated by the bathymetry of the shoreline. A three foot swell at 20 second interval can make a big freaking wave if there is an underwater canyon funneling the swell, such as at the shores launch or blacks.