BIG, BAD WAVE: A monster rogue wave approaches a merchant ship in the Bay of Biscay, an arm of the Atlantic Ocean bordered by the coasts of northwestern Spain and southwestern France.
Image: NOAA'S NATIONAL WEATHER SERVICE COLLECTION
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A near-vertical wall of water in what had been an otherwise placid sea shocked all on board the ocean liner Teutonic—including the crew—on that Sunday in February, more than a century ago.
"It was about 9 o'clock, and [First Officer Bartlett], as he walked the bridge, had not the slightest premonition of the impending danger. The wave came over the bow from nobody seems to know where, and broke in all its fury," reported The New York Times on March 1, 1901: "Many of the passengers were inclined to believe that the wave was the result of volcanic phenomena, or a tidal wave. These opinions were the exception, however, for had the sea been of the tidal order Bartlett would have seen it coming." The volcano theory was just as unlikely: "Absurd, absurd," one of the Teutonic's officers told the Times. "It was a giant sea, and there is no doubt of that."
This is just one of the many anecdotal accounts in maritime history of waves upward of 30 meters devouring ships, even swallowing low-flying helicopters. But what sea captains and scientists have long believed to be true only gained widespread acceptance after the first digitally recorded rogue wave struck an oil rig in 1995. "The seamen tales about large waves eating their ships are correct," says Tim Janssen, an oceanographer at San Francisco State University. "This was proof to everybody else, and a treat for scientists. They suspected it, but to see it and have an observation is something else."
Now that there is no longer a question of rogue waves' existence, other mysteries have arisen: How frequently do they occur? Just how do they come about? Are there areas or conditions where they are more likely? Janssen is among a growing group of researchers in search of answers to these questions, which could someday lead to safer seas.
Rogue waves by the numbers
Before any answers could be attempted, scientists first had to characterize a rogue (or freak) wave. The widely accepted definition, according to Janssen, is a wave roughly three times the average height of its neighbors. This is a somewhat arbitrary cutoff. Really, he notes, they are just "unexpectedly large waves." The wave that swept onlookers off the coast in Acadia National Park in Maine on August 23 may not fit the former definition, for example, because background waves were already quite large due to Hurricane Bill, and rogues typically occur in the open ocean. Yet that wave has still been readily referred to as a "rogue".
No one is certain yet just how frequently freak waves form; accurate numbers are extremely difficult to collect given the waves' rare and transient nature. With more sophisticated monitoring and modeling—and as first-hand accounts are taken more seriously—the waves' prevalence appears to be rising. "[Rogue waves] are all short-lived, and because ships are not everywhere, the probability that a ship encounters one is relatively small," says Daniel Solli, who studies the optical version of rogue waves at the University of California, Los Angeles. "But with increasing amounts of oceanic traffic in the future, the likelihood of encountering them is getting larger."
Some areas seem to breed the waves more than others. Janssen and his colleagues recently used computer models to determine that regions where wave energy is strongly focused could be up to 10 times more likely to generate a freak wave. He speculates that approximately three of every 10,000 waves on the oceans achieve rogue status, yet in certain spots—like coastal inlets and river mouths—these extreme waves can make up three out of every 1,000 waves. A paper describing these results was published last month in the Journal of Physical Oceanography.
Forming fearsome waves
Various theories exist for how rogue waves form. The simplest suggests that small waves coalesce into much larger ones in an accumulative fashion—a faster one-meter wave catches up with a slower two-meter wave adding up to a three-meter wave, for example. Janssen and his colleagues build on this with a more complex, nonlinear model in their recent paper. Waves might actually "communicate—sometimes in a bad way—and produce more constructive interferences," Janssen explains. By communicating, he means exchanging energy. And because the conversations aren't necessarily balanced, he says, "Communication can get amplified enough that a high-intensity large wave develops." In other words, one burgeoning wave can actually soak up the energy of surrounding waves.
Again, in those places where variations in water depths and currents focus wave energies, this line of communication can get especially busy. Janssen's models identified these rogue-prone zones. Certain conditions such as winds and wave dissipation, however, could not be included, limiting the simulation's predictive power.
Meanwhile, Chin Wu, an environmental engineer at the University of Wisconsin–Madison sees another likely scenario spurring the monster waves: "If a wave propagates from east to west, and the current moves west to east, then a wave starts to build up," says Wu, who studies wave–current interactions in a 15-meter pool. The wave basically climbs the current's wall, rising out of what appears to be nowhere. Rogue waves have in fact been more common in regions such as the east coast of South Africa where surface waves meet currents running in the opposite direction.
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10 Comments
Add CommentEven a small speedboat can create a wave much larger than itself by steadily turning in a shallow arc. As the concave side of the wave front "sums", the wave steadily increases in size. Is it possible that the apparent increase of reported rogue waves may be due to large, slow-turning massive boats (think supertankers) hundreds or even thousands of miles away? Could satelite surveillance determine this?
Reply | Report Abuse | Link to thisI kind of agree with jjrs5, but I also seem tp recall a TV broadcast within the last year that reported that several satelites filming areas of the oceans had detected "ROUGH WAVES" and they were more common than first thought. It also seems to me that an Oceanographer(sp) was triing to develope a computer program that could forcast these waves based on data supplied by ocean bouys now in place. Although this would not cover all such waves, due to the nature, in would help out. I personally wonder if undersea tectonic activity, at a distance from the observed wave, could also supply the energy that is needed,in part, for this event. Just as one wave appears to be able to harness another wave's energy could the tectonic energy be harnessed by a wave in conjuction with wind/current energy and then further applified by undersea topograph just as storm surge can be. This in turn brings to mind an even in Florida, earlier this year I think, where sudden exceptional waves inundated a popular beach, luckily late at night when no-one was there. Good luck on all research on this. So far as I know only a few cruise ships and passenger liners have had the misfortune of encountering these waves and they survived, the same for tankers and cargo ships, BUT one day luck will run out.
Reply | Report Abuse | Link to thisI've seen a rouge wave in the Gulf of Mexico at 2am, and I can say for certain it is as scary as you can possibly imagine.
Reply | Report Abuse | Link to thisChapter 31 in the book Heavy Weather Sailing by Coles and Bruce discusses wind waves,the influence of geographical features and currents very well. The book includes the results of scientific research including satellite data. It also presents Geostat mean signicant wave heights for various years and locations.
Reply | Report Abuse | Link to thisInterestingly the Agulhas Current of South Africa where quote " high north-east- going waves from the Southern Ocean run into the strong south-west-going current with dramatic effect".
In addition to freak waves of extreme height the opposite exists where deep troughs or "holes" have been reported. (It has been speculated that unexplained disappearences of large vessels may be due to foundering in such "holes"). There is a report of a 500ft merchant ship which met such sea conditions and would have gone to the bottom if its deck hatches had not been securely battened, even thogh it was extremely hot and humid with passengers below deck.The windows of the pilot house 80 feet above deck were stove-in as a result of this encounter.
A considerable amount of investigation has been done on the subject of waves and the scientific community should perform a thorough literature search on the subject.
I really wish editors of general scientific publications would ask authors to reduce or eliminate giving natural events human characteristics, waves having a "conversation" - or comparing giant waves as "monsters". That needs to stop.
Reply | Report Abuse | Link to thisIt simply gives false connotations as to what these events are.
jjjrs5 may be on to something. As a meterorologist, intense surface low pressure centers over the ocean may form max low level wind bands that over time rotate in a propagating arc path. These bands can converge into a single area like bananas coming closer towards one head or point of contact. Superposition of these waves could lead to a rogue. Thus depending on the strength and track, the area of concern could be forecasted. Most marine forecasters foecast where the highest sea state will track, but I believe more effort is needed in where current/bathmetry/and previous swell height and track (angle of incidence with respect to highest sea state) intersect for the non-linear theory to spark.
Reply | Report Abuse | Link to thishaving spent the better part of my life on the ocean as master of various merchant vessels, I have encountered freak waves a few times... I have never seen one in deep ocean waters. in gale conditions waves always travel in series of 7, with # 1, 2 and 3 getting gradually larger, culminating with # 4, and then getting smaller with # 5,6 and 7.any navigator knows that, as one takes advantage of this if it is necessary to make a 180 and turn the stern to the weather and run before it. although # 4 can be very large, it hardly qualifies as a rogue...
Reply | Report Abuse | Link to thisthe greatest danger is really not the actual rogue wave but the ship diving into the trough behind it. especially for very large ships, that due to their immense mass are unable to rise to the next wave and therefore gets swamped. failure to reduce the ships speed in adverse conditions is also contributing to the severity of the damage damage done. rogue waves has a short life, measured in seconds as gravity begins flattening them as soon as they occur, so damage to ships are caused by a rogue wave being formed in close proximity to the ship and the vessel ramming it at full speed. the problem was much smaller when merchant ships were hard pressed to make 7 0r 8 kts. todays flimsily build giant empty steel boxes (think cruise ships) travelling at close to, or in excess off 30 kts are indeed in trouble if they run into any wall of water.
as for the "poseidon"wave .... well, you heard of the giant octopus that swallowed a 10.000 ton ship.
tsunami you say...not visible or noticeable at sea, less that a foot high, it can be very wide and travel at 400 kts....but get away from the beach when the water starts to recede...
Adlard Coles made me curious,as a young ocean-sailor,about HEAVY WEATHER.
Reply | Report Abuse | Link to thisNow after nearly thirty years at sea,mostly in sailing vessels,in the central,southern and western pacific I am not as curious as I was once.
My question about rogue waves was answered in 1990 off the coast of LUZON,the PHILIPPINES,not far North of SanBernandino Strait.
I was operating a 65foot work-boat,very heavily built,and was bound for the Strait and South to my base.
The sea-state was reasonable,a large swell(15ft),and few breaking waves.
The wind,direction and force,were normal for the season at about 15knots from the North-East.
My answer,the wave,came over the Port side and it was big.
It; broke over the bridge and removed the capsule life-raft and smashed it on the starboard after-deck,blew in all but two non-opening ports on deck-level port-side leaving four-feet of sea-water in the crew berthing space and the galley.
A bit less water in the engine-room allowed the diesel to continue running.It was the diesel,and three very frightened men with buckets,that kept us afloat.Because we had zero free-board it was possible to steer only directly into the weather,out to sea.
All electrics and electronics were out.
The main hatch-cover was gone as was the antenna-mast.
Anyway it is an old event that came back to mind when I saw the article.Some of the happenings of that day are worth a good laugh now but at the time it was a starkly serious situation.
I have never understood how Coles et.al. survived the fug in the fore-peak of COHOE
That was my one experience(so far)with rogue-waves
Rogue waves are always going to be with us but it's technologically possible to build sea-going craft that are invulnerable to waves - gimballed and weighted spherical craft within spheres. It'd be a rough ride but it would end flip-overs and bring new meaning to re-surfacing and docking. Probably be noisy too. Couldn't be any worse though than putting up with days of pitching, yawing and rolling. 100 foot drops would add to the thrill but bouyancy variances could reduce vertical extremes in big seas...and speed would be compromised.
Reply | Report Abuse | Link to thisNot sure I could sell this idea to Disney or Carribean Cruise Lines - but bulk carriers - given their potential to pollute if they break up - could well do with a whole new approach to shipping and rogue waves.
BMR
I think this phenomenon is called butterfly effect.
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