Rogue Wave Prediction

[boatman61]

Originally Posted by gsuescum

I may be wrong but is my understanding that rogue waves appear suddenly and go away just as quickly. They aren’t waves that cross oceans or travel for any significant distances that can be tracked.

I thought they came to be from constructive interference of other waves. In that case they would usually tend to appear very quickly, break, and then disappear.

[Tillikum]

Originally Posted by dannc

What is true, yet is insulting from arrogant "scientists," is that sailors have been experiencing rogue waves for centuries but were not believed.

Originally Posted by GordMay

Rogue waves, called 'extreme storm waves' by scientists, are those waves which are greater than twice the size of the significant wave height of the area [surrounding waves].
The significant wave height is the average of the highest one-third of waves, that occur over a given period.

“All truth passes through three stages. First, it is ridiculed [by "experts']. Second, it is violently opposed [by "experts]. Third, it is accepted as being self-evident [by the same "experts"].” Schopenhauer

And the fourth stage is pretending to themselves and others that they thought so all along.

[PippaB]

Originally Posted by wholybee

...But, I don't think they are frequent. I have heard sailors talk about a "rogue" wave hit them infrequently but also regularly during a passage. Like once a day, or once every couple days. Sometimes they are even described as hours apart. I suspect that if there were a buoy measuring those waves, they would not be twice the significant wave height, and would be part of the normal wave sequence. Thus, not a rogue wave....

One estimate puts rogue waves (as defined by 2xSWH) at 3 /10000. If you have an 8-second wave period that conveniently works out to ~10000 waves/day, which then yields one rogue wave every 8 hours. For a 16-second wave period you're at half that, and for a really long 24-second wave period you're at one rogue/day.

So, with the assumption that 3/10000 is somewhere in the realm and is backed by the science (several papers on this frequency question) it would not only be common, but would be expected that a passagemaking yacht would encounter 1-3 rogue waves per day.

[MicHughV]

My 2c is....that a roque wave, the definition of which is not clear, seems to occur when two or more waves interlock momentarily for a relatively short period of time, probably out of sequence to the general wave pattern, you could say that one wave climbs on the back of another, ie, a 15' wave climbs onto another 15' wave, and for that moment in time, it becomes a 30' wave.

Wave studies and sea state are modeled by companies that specialize in these things for the offshore drill platforms, etc.

They'd be a good source of info if they were to share such knowledge.

[boatman61]

Since my first W-E Transat in 2000 I have only experienced what I presume was a rogue wave once though I cannot confirm as I was below deck at the time..
There was a massive crash up forward and the whole boat shuddered and stopped abruptly.. I charged on deck thinking I had hit something but nothing was in sight bar an aircraft carrier W bound on the Northern horizon, no damage at the bow so ran back down to check the bilges, that's when I discovered the Fore bulkhead punched out and lying across the berth, the main central bulkhead had several tabs broken on the port side.
This happened N of Bermuda while a low was passing and had hit me with NW and N winds and was building to a NE blow.
Sea's were moderate with swells maybe 2.5 metres plus wind waves on top.. the couple of hours between wind shift had quietened things down a tad, wind F6 and rising.

https://scitechdaily.com/the-mystery...ver-key-cause/

[wholybee]

Originally Posted by PippaB

One estimate puts rogue waves (as defined by 2xSWH) at 3 /10000. If you have an 8-second wave period that conveniently works out to ~10000 waves/day, which then yields one rogue wave every 8 hours. For a 16-second wave period you're at half that, and for a really long 24-second wave period you're at one rogue/day.

So, with the assumption that 3/10000 is somewhere in the realm and is backed by the science (several papers on this frequency question) it would not only be common, but would be expected that a passagemaking yacht would encounter 1-3 rogue waves per day.

But, if a wave occurs 3 times per day, then it is a regular occurrence, and can't be a rogue wave, regardless of size. And remember 2xSWH is *not* a rogue wave. 2xSWH is an expected wave height. With that in mind, I have 30,000 miles of ocean sailing. I can tell you with high confidence that a rogue wave does not happen every 8 hours.

[wholybee]

This is worth a quick read. Especially the point that a wave 2xSWH will happen about once per hour. That is NOT a rogue wave.

https://www.weather.gov/mfl/waves#:~...on%20a%20beach.

[PippaB]

You want to make up your own definition based on your understanding of the word 'rogue', but in the literature 2xSWH is the definition of 'rogue wave'.

A rogue wave is usually defined as a wave that is two times the significant wave height of the area. The significant wave height is the average of the highest one-third of waves that occur over a given period. Therefore, a rogue wave is a lot bigger than the other waves that are happening in its vicinity around the same time. https://education.nationalgeographic...e/rogue-waves/

In oceanography, rogue waves are more precisely defined as waves whose height is more than twice the significant wave height (Hs or SWH), itself defined as the mean of the largest third of waves in a wave record. https://en.wikipedia.org/wiki/Rogue_wave

Rogue wave, a relatively unpredictable and unexpectedly high water wave arising at the water’s surface and formed from the coincidental stacking of multiple wind-driven wave crests passing through a single point or arising from a combination of waves and currents that may shorten the waves’ frequency. Rogue waves tower to heights greater than twice the size of nearby waves, and they may move in either the same direction, the opposite direction, or at oblique angles to the prevailing wind and wave motion. https://www.britannica.com/topic/rogue-wave

But what, exactly, is a rogue wave? When scientists talk about wave height, they tend to focus on the tallest one-third of the waves in an area. They call the average of these the “significant wave height.” No matter the weather conditions, waves vary in size. It’s those taller, significant waves that have the most energy and are most likely to cause damage. They’re also the best ones for surfing. For a scientist to call a wave rogue it has to be at least twice as high as the significant wave height in the area. The most extreme rogue wave recorded was three times taller [emphasis added]. But unless instruments are taking measurements, it’s hard to say if a wave qualifies as rogue, especially in stormy seas. https://www.whoi.edu/know-your-ocean...-a-rogue-wave/

A rogue wave, also known as a freak wave, is a large and unexpectedly high ocean wave that occurs in open water. It is defined [emphasis added] as a wave that is more than twice the height of the significant wave height (SWH), which is the average of the highest one-third of waves at a given location. https://www.americanoceans.org/facts...-a-rogue-wave/

[lestersails]

Originally Posted by Tillikum

And the fourth stage is pretending to themselves and others that they thought so all along.

I appreciate that it currently fashionable to ridicule experts, researchers, and 'elites' (whatever the h3ll that means). But it remains true that conclusions require evidence. And extraordinary claims require extraordinary evidence. (Carl Sagan)
https://en.wikipedia.org/wiki/Extrao...inary_evidence
We should all be skeptical of extraordinary claims. And we should all be willing to change our minds when the evidence changes. "When the facts change, I change my opinions. What sir, do you do?" (Paul Samuelson). That is the way the scientific method works.
It might soften one's fragile ego to ridicule researchers. But it is the only way to knowledge. Or your can just go with voodoo, Tarot cards, palm readers, and religious mystics.

[MicHughV]

Boatman, that #@!$%#%$% Bermuda weather!!!

Worst weather I've ever been in was just south of Bermuda. Had my ears well and truly pinned by wind and waves the like I've never seen before.

But I possit another theory.

Along the ocean floor in the Atlantic are many " sea mounts". These affect wave heights in no uncertain manner.

Just my 2c here, but once past Florida, the Gulf Stream meanders all over the place, and when the Gulf Stream current meets these seamounts, who knows what transpires beneath the waves.

I tried to attach an ocean map showing the Gulf Stream meander, plus all the spin off currents, and it's quite a mish-mash, but I wasn't able to attach the link.

But you'll find it here:

https://spaghettimodels.com/

[Tillikum]

Originally Posted by lestersails

I appreciate that it currently fashionable to ridicule experts, researchers, and 'elites' (whatever the h3ll that means). But it remains true that conclusions require evidence. And extraordinary claims require extraordinary evidence. (Carl Sagan)
https://en.wikipedia.org/wiki/Extrao...inary_evidence
We should all be skeptical of extraordinary claims. And we should all be willing to change our minds when the evidence changes. "When the facts change, I change my opinions. What sir, do you do?" (Paul Samuelson). That is the way the scientific method works.
It might soften one's fragile ego to ridicule researchers. But it is the only way to knowledge. Or your can just go with voodoo, Tarot cards, palm readers, and religious mystics.

I see you make no "hillbilly" remarks this time; got that impulse wrestled down I suppose, lest it reveal too much??

What you perceive as "ridicule" is merely a healthy degree of common sense and skepticism in most cases. Certainly those who have been harmed or had family members harmed by the advice or direction of so-called experts might be expected to engage in ridicule at the very least, but happily I am not one of those.

The real problem is the monumental self-conceit of "experts" and their wonderful ability to imagine themselves as the Don Quixote's of knowledge when the oldest profession is usually a more apt metaphor. A trend which parallels the decline in public and private morality and indeed in the existence of moral sense all. The contempt if not actual hatred often displayed for the "others" of humanity speaks volumes.

That is moral sense as in founded on a set of moral values rather than what is now mostly confused with it: a contemptible conformity and mob mentality which has never in all human history been associated with any kind of intellectual, moral or "scientific" advancement, and is in fact the polar opposite of it. A fact so obvious that the current blithe indifference to it is probably enough to charge if not convict as a group those who should be the most aware of it.

Those who cannot stomach criticism or are hyper-sensitive to it are the emotionally fragile. Those whose self-esteem is founded on their purported expertise and little else, naturally react violently to whatever their perceive as an attack on it as their whole self-image is often at stake. Used to the deference of perceived inferiors such people often come to match quite closely the psychological profile of the classic narcissist.

And history certainly shows what they are capable of.

[Don C L]

Originally Posted by Bmorgan562

Scientific definitions and actual experience IMO will feel different. If at some point you are cruising and say "oh **** look out!" that's a rogue. In all seriousness as someone mentioned here they are acknowledge to finally exist, and, definitions and understanding can and do change over time. Not a really exciting story but here it is anyhow . One time I was traveling through the Catalina channel on a very very quiet calm no wind Southern Californian day Flat flat flat. I 100% saw at rolling breaking approximately 1 foot wave. It had no discernible reason to be there (unless a Sub just past through under) But to me there was no reason for existence it was amazing. Rogue wave? I don't know because it doesn't fit the definition it actuality and proportionally much much larger. for what its worth..

I saw one like that in the Santa Barbara Channel too once. A large breaking wave, distinct from all others, rolling along for no apparent reason. I was flying with my father at the time and we both immediately said, "Look at that!" But it was easy to see that a boat has to be in the right place at the right time to see a wave like that. Chances are we all may have passed a rogue at one time and either did not know it or saw it in the distance. This would be especially true in areas where currents collide or wind and currents are at odds. I know I have seen some pretty big waves off our Point Conception locally, but I wasn't in the mood to try to measure them accurately at the time for rogue status. It was just the universal "Oh ****!" measurement.

Still I for one would love to get an announcement over the radio that there is an X probability for a rogue wave at X lat and X long within 5 minutes. Any kind of a heads up is welcome, even if it is a false alarm IMO.

[shimari]

Originally Posted by GordMay

... And, real-time access, to their data, aboard a yacht.

Starlink is making this possible, but I agree not accessible to most.

The T-mobile integration with Starlink may make it more accessible for alerts. The customer sends location data to a server that tracks their location and then sends alerts based on location and buoy data. Those messages are all pretty small and won't consume too much data. All of the computations are done in the 'cloud'. I'd argue this is closer than we think.

[wholybee]

Originally Posted by PippaB

You want to make up your own definition based on your understanding of the word 'rogue', but in the literature 2xSWH is the definition of 'rogue wave'.

I'm not making anything up. 2xSWH is the dividing line. All of your quoted definitions except the first say that a rogue wave is _greater_ than 2xSWH. Only one of your quotes says that exactly 2xSWH is a rogue wave. The regular and predictable wave pattern includes waves that are 2xSWH. So, I consider that first quote a mistake because it both doesn't agree with the majority, and because a rogue wave is not a regular occurrence, so a wave in the normal wave pattern isn't a rogue wave.

I would also consider NOAA an expert and reliable source on the definition. And NOAA uses "greater than" twice the wave height, that they are unpredictable, and that they often come from directions other than prevailing wind and swell.

We are splitting hairs here on "greater than" vs. "equal to or greater than". But, it is important to realize that very large waves up to but not exceeding 2xSWH happen often and with a regular interval. A rogue wave does not. There just isn't any way a wave in the regular wave pattern would be a rouge wave.

https://oceanservice.noaa.gov/facts/roguewaves.html

[El Pinguino]

Originally Posted by wholybee

There just isn't any way a wave in the regular wave pattern would be a rouge wave.

https://oceanservice.noaa.gov/facts/roguewaves.html

Rouge waves are quite common in the Red Sea.

The average punter sailing downwind in the trades won't be bothered by them.. OK so with a wave train of say 2 metres a 4 metre jobby come rolling through it isn't exactly the end of life as we know it.

I've only encountered one, south of Mar del Plata, poking along to windward under reduced canvas, just back from the mast having tucked another reef in.
Swept the deck clean, lucky it didn't take me as well.

Dunno how that would have been forecast .

The conditions where serious 'rogue wave' conditions exist - the western approaches to Europe , Bass Strait, Chile, etc, in winter tend to be places where sensible sailors aren't sailing anyway