Deadliest Catch: Crabbers Face Brutal Seas off Alaska Coast

[glondor]

Thought I would post this gem. I have experianced something similar to this in the early 1980's in the caribean. Very scary. This put a spotlight on the power of the sea. This is a clip from the discovery channel's show "deadliest catch" About crabbers off of the Alaska coast. They get smashed. Hard.

 

[Greg Bernhardt]

Aren't true rogue waves, massive waves, that come out of seemingly calm water? I saw a discovery show on them.

 

[Ivan Seeking]

Thought I would post this gem. I have experianced something similar to this in the early 1980's in the caribean. Very scary. This put a spotlight on the power of the sea. This is a clip from the discovery channel's show "deadliest catch" About crabbers off of the Alaska coast. They get smashed. Hard.

Until recently rogue waves were considered to be a mariner's myth. However, technically that probably wasn't a rogue wave. These guys were in 40 foot seas and got hit by a 60 foot wave. Rogue waves often occur in otherwise calm waters and weather; they can reach heights of 100 feet, and they often come from a different direction than that of the normal swells.

Not too long ago, in the news was a large passenger liner that was hit by an 80 footer that seemingly came from nowhere. Rogue waves have also been measured hitting oil rigs where the wave shape could be ascertained using strain gauges and other monitoring equipment built into the rig. Allegedly, at least one rogue wave matched the shape predicted using non-linear wave equations. So it appears that the reason these waves weren't predicted before is that the shipping industry has been using linear wave models for the last century. Until rogue waves were finally observed on satellite images, they were generally believed to not exist because they couldn't be explained using the linear models.

 

[Ivan Seeking]

Heh, I made the post above after pulling an all-nighter and before getting any sleep. Late edits.

 

[hypatia]

I've seen mini rogue waves{15 to 20 ft} on Lake Superior, and of course being a lake, they make landfall much like a mini tsunami.
The boat in the video clip really took a knocking! They were very lucky.

 

[Huckleberry]

I experienced something like this while I was in the navy. The weather was stormy and I was sleeping in my rack. I was awakened when the ship began to tilt sharply and I was stopped from falling out of my rack by a small railing. The ship continued to roll in that direction slowly and I had to hang onto the railing to stay in my rack. Then the ship righted itself and I went back to sleep, but for a few moments there I had my heart in my throat. I was on an 800' amphboius carrier.

It might not have been a rogue wave, but it's standard procedure to direct a ship into the direction of the waves in heavy weather. This wave came from the starboard side.

 

[glondor]

I dissagree. What makes this a rogue is the fact they were (and this is something you must do in these conditions) powering into the waves. In these conditions, you cannot go "with" the waves as you will surf or be pooped. If you surf, this can break the back of your boat. If you don't surf you run the chance of the waves breaking over your stern, (being pooped) and hammering your boat under. There is only 1 course of action you can do and that is to power thru the oncoming waves and take them over the bow. The waves all run in the same direction so it is relativly easy to determine which way to go. The rouge came at them from the starboard side almost broaching the ship. This wave was moving ACROSS the direction of travel of the running seas at the time. We know the direction of the seas as the captain has no choice but to keep his bow pointed in that direction. This came from the side.

explanations- broaching a ship . There is a pic at the bottom of the page of a surfing ship being hammered down http://www.worldwideflood.com/ark/anti_broaching/wave_yaw.htm

being pooped- http://books.google.com/books?id=vU...ts=0oUbLRbhYi&sig=ggsO0Clh0qXC2UHvjyIyH5z4las

 

[Ivan Seeking]

The key is whether a wave like this can be predicted using linear models. Wave interactions can be highly complex, and even linear models allow for rare but large waves that may not be expected. Without knowing more about the area and conditions, to call this a rogue wave is premature at best.

If you start calling every unusual or large wave a rogue wave, you will water down the definition.

 

[Moonbear]

The key is whether a wave like this can be predicted using linear models. Wave interactions can be highly complex, and even linear models allow for rare but large waves that may not be expected. Without knowing more about the area and conditions, to call this a rogue wave is premature at best.

If you start calling every unusual or large wave a rogue wave, you will water down the definition.

In stormy conditions, are you necessarily going to have all the waves going in a single direction? I've been out on rough water that was all chop rather than rolling waves, and it seems quite possible that in a storm you'd get something like that too, especially if the wind is changing direction.

The Bering Sea is quite stormy through much of most every winter. But the nature of these storms varies a great deal. One type of atmospheric circulation pattern produces a parade of cyclonic, low-pressure systems from the southwest

http://www.beringclimate.noaa.gov/essays_bond.html

 

[Ivan Seeking]

In stormy conditions, are you necessarily going to have all the waves going in a single direction? I've been out on rough water that was all chop rather than rolling waves, and it seems quite possible that in a storm you'd get something like that too, especially if the wind is changing direction.

The local and even distant topography has to be considered as well. One might encounter waves that are wind generated as well as reflected waves from distant shorelines. In fact in some areas like the South Pacific Islands, reflected waves were once used by early sailors and seagoers to navigate the oceans.

Also, the principle of superposition still applies. Linear models do predict that waves can interfere constructively to produce exceedingly large waves, but there is a limit on what we expect... I think something like two or three times the size of the normal swells. Beyond this it appears that we need the non-linear solutions to explain waves that are proportionately larger. As reported, in some cases a rogue wave may be ten or twenty times the size of the other observable waves.

 

[jim mcnamara]

ESA research summary on waves with height > 7m based on satellite data:

http://eopi.esa.int/esa/esa;jsessio...28371&table=progressreport&cmd=image&id=10180

 

[glondor]

I kinda thought, considering the location, perhaps the storm calved a few big bergs off of a glacier or two creating this rogue. only a thought.

 

[Poop-Loops]

Would this be a rogue wave?



NSFW due to swearing, but otherwise it's just a wave.

 

[glondor]

Here is a very nice documentary about freak waves, the search for and the cause of some of them. It cannot explain all occurrences however. It is about 48 minutes long. worth a look for some of the explanations and the quantam theory connection. (Non linear waves)
hope the link is functioning.

http://quicksilverscreen.com/watch?video=32537

 

[Ivan Seeking]

An article about Rogue Waves from Scientific American:

...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...

http://www.scientificamerican.com/article.cfm?id=rogue-waves-ocean-energy-forecasting

 

[Pattonias]

Wouldn't a rouge wave potentially occur in the same manner as a tsunami?
A tsunami is a result of seismic activity under the ocean surface. The shock wave travels through the water until it hit shallower water. The kinetic energy of the water carries the water onto land because of the rising level of the ocean floor.
If you had an underwater earthquake and the resulting shock wave came into contact with an underwater mountain or shallow; wouldn't you then have a rouge wave?

 

[Huckleberry]

Wouldn't a rouge wave potentially occur in the same manner as a tsunami?
A tsunami is a result of seismic activity under the ocean surface. The shock wave travels through the water until it hit shallower water. The kinetic energy of the water carries the water onto land because of the rising level of the ocean floor.
If you had an underwater earthquake and the resulting shock wave came into contact with an underwater mountain or shallow; wouldn't you then have a rouge wave?

No, they aren't the same thing. Tsunamis have a large wavelength and a very small amplitude as they travel the ocean. Rogue waves have an uncommonly large amplitude for any given sea state.

 

[Pattonias]

No, they aren't the same thing. Tsunamis have a large wavelength and a very small amplitude as they travel the ocean. Rogue waves have an uncommonly large amplitude for any given sea state.

Ah, I see.
I don't guess enough data (at least I can't find any) has been collected to compare rouge wave activity to coastal tide levels. I wonder if they could be attributed to a lunar phenomenon...

 

[Ivan Seeking]

Apparently, as referenced by Huckleberry, based on not only the little experimental evidence that exists, but also one or more non-linear models, a true rogue wave has a very short wavelegth as compared to a normal wave of the same size. Non-linear modeling does predict their existence.

To my knowledge, satellites, and the one incident with the oil rig in which sensors were in place and active when a rogue wave hit, provide the only hard data that exists.

It seems that we are beginning to understand what causes these monsters.

 

[pallidin]

Complex, constructive wave interference?