Set wave pattern?

[BoMan]

In your experience, which wave in a set is most often the biggest?

[jaffa1949]

Depends on the swell,train , longer fetch might set a numbered sequence, 7 and 9 are bandied around, chuck in a a rogue or two, a fraction of diffraction and refraction, the subtraction of the reaction, just know in heavy wave zones the first wave of the set is not the one to,either miss catching or to wipeout on. That is called meet our bigger brothers, be it on your head!

The longer fetch allows the storm that produced the original waves to have them organised into trains with longer interval. Orbwave lengths (= more power with the longer wave length period) the sets are are wave length phenomena too as faster waves over run slower waves and either add to,or diminish the swell height. Less wavesvare overwhelmed and disappear leaving gaps in the wave train.... over a longer fetch any arythmia is cancelled out and the conditions at the point of arrival,bear no resemblance to the place of origin.
Think Aleutian Arctic Bering strait winter storm making the December January swell for the north shore of Hawaii.

[oldmansurfer]

The one that gets me? I think it depends on the day. Usually the first wave isn't ever the best wave but some days it is.

[oldmansurfer]

I used to paipo board at a break that routinely had cleanup sets. So it would be breaking at 6 to 8 foot (up to 16 foot faces) then every ten minutes 2 waves would come in that were may be ten foot (20 foot faces) and they would break about 30 yards out from the lineup for the rest of the waves. It was a really good paipo boarding spot because I could "duck dive" all the ways to the bottom and avoid any pounding whatsoever. Surfers would come out and then in ten minutes just like flushing the toilet they were all gone and it would take them another 10 minutes to get back out then right back to shore they go. It was really great I would dive down under the wave completely and come back up to being alone in the lineup again. One of the surfers wanted to trade boards with me because he wanted to get tubed like I was getting Man I had some really great tube rides on both the days I hit it like that. I suppose the surfers could have paddled out to where the cleanup sets were coming in but those waves weren't tubing out so much.

[BoMan]

The one that gets me?

Yep, it happens way too often....I sit forever waiting for a ride and get impatient. A 3 footer rolls-in which I catch it for a short ride, and then the BIG WAVES come and make me pay for going too soon!

[RinkyDink]

The one that gets me?

Yep, it happens way too often....I sit forever waiting for a ride and get impatient. A 3 footer rolls-in which I catch it for a short ride, and then the BIG WAVES come and make me pay for going too soon!

See, I'm the guy who knows better. When you go for that three footer out of frustration, I stay the course and keep waiting. Waiting . . . waiting. . . waiting. Eventually even I throw in the towel and paddle for a three footer. And that's when the really good, truly BIG WAVES come. I wait long enough to where when I go for the three footer everybody in the lineup thinks, "Haha, that guy just waited outside for 30 minutes, took off on a junk wave, and now the set waves are here."

[waikikikichan]

It’s not the size, but the shape that matters. Depending on the break, the first one might not have “shape” compared to later ones. At other break the earlier ones are clean(er) and the laters ones get back wash or bumps. At some breaks the kooks who are too hungry for waves go for the first, let them get cleaned out, then go for the empty point/peak on the 3rd / 4th one.

[benjl]

One thing I've never understood is that in nz our west coast tends to get 3-wave sets.
However when I was in Fiji and cloud break they seemed to get relentless sets up to to 7 waves on some sets.

Out east coast on hurricane swells seems to get around 4-5 waves in a set?

For our waves, normally the second or third in a 4 wave set is the biggest.
Learned from experience that you never fall for the first one.. especially in places like Fiji!

[dtc]

waves are formed by wind blowing ripples into the water. As the ripples move along the ocean, some are bigger and faster than others, some are smaller and slower. The faster ones catch up to the smaller ones and form even bigger ones. Which in turn catch up to the next ones etc.

However, the extent to which this can happen depends very much on the distance the ripples travel (called 'the fetch'). So west coast of NZ, the ripples can only travel a short distance (Australia to NZ), where as Fiji they can travel a huge distance.

If there is a short distance, then while some of the ripples catch up to each other, many dont. This means there are lots of small to medium ripples which turn into waves ie shorter period waves. However, the sets only have a few waves in them - there are set waves and then smaller waves and then another set.

When there is a long distance, most of the ripples have caught up to each other. This means fewer waves (longer periods) but the waves are often bigger/more powerful and the sets have more waves in them (because more of the ripples have caught up to each other ie there are a few waves, then nothing, then another set).

Overall the 'total' amount of water moving will be the same (assuming identical wind and other conditions). But where there is a small fetch, water is split between lots of smaller to medium waves. Where there is a long fetch, the water is generally just bigger waves and not many small waves.

note: obviously Fiji has smaller waves at times eg when the wind causing the ripples was blowing quite close to Fiji.

[benjl]

cheers DTC, that's fascinating!

Note our west coast has cleaned up this coming weekend and reporting 1.8m waves at 17secs, which is small-ish by our west coast standard but a lot longer swell period? Normally it's around 12sec @2m ish.
Does this mean smaller but more powerful waves?

Our east coast in stark contrast typically has a 5sec period with about 0.4m swell height unless there's a cyclone and it boosts up around 1.5-2m @ 10-15sec.

[Big H]

4-5 wave sets the third is the biggest here.

[dtc]

17 second period will usually mean powerful waves - a good explanation in the link below. But note the para right at the end.

https://magicseaweed.com/help/forecast- ... d-overview

The other thing to keep in mind is that long periods from deep water = powerful waves (eg Fiji, Hawaii). Long period coming in over a shallow continental shelf (eg parts of UK) and the swell slows down (long period) but becomes weak due to dragging on the ocean bed taking its energy

This forecast site does some ‘magic stuff’ to combine size and period etc into an energy figure - like all forecasts it may or may not be totally accurate for your specific location, but it will give a general idea

http://www.surf-forecast.com

[Big H]

I was going to go out tomorrow....2523 is the wave power....not really sure what that means other than the literal joules description; no practical reference yet but I'll start to look at the chart after going out, after a month I'll have a better idea. TQ DTC.

[dtc]

2523 is pretty strong. Of course, as with everything, 'it depends'. 2500 at my beach break would be 2OH or more; but on a reef or point it might be OH. Either way should be quite powerful.

In any case, as Big H says, spend a month looking at actual conditions vs forecast conditions and see how useful it is - knowing that X kj for your break means a wave of certain strength and size, and then you can adjust from there for your particular location. So (for example) 1000kj is fun, so 500 is pretty weak and 2500 is getting a bit big (or whatever); appreciating that for another location those numbers might be 500 fun, 150 weak and 1500 too big

[saltydog]

The one that gets me?

Yep, it happens way too often....I sit forever waiting for a ride and get impatient. A 3 footer rolls-in which I catch it for a short ride, and then the BIG WAVES come and make me pay for going too soon!

That’s so me...

[benjl]

I was gonna say the same dtc! I used to follow that website and 2500 at my local would be a decent wave.
That's usually around 2-2.5m here.

My local is hitting over 7000 joules next week on a day when there's close to 5m waves and a danger sign on the website