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Old 01-08-2013, 09:57 AM   #1
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FREAK WAVE (BBC Doc)

Sweet dreams kiddies

Part one of five;

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Old 01-08-2013, 03:57 PM   #2
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Interesting program. I watched all five segments of the series and was struck by a couple of things.....

--In the second of the series where they were studying waves off the southern tip of Africa they determined that the large waves were generated when the current ran in the opposite direction of the wind and main current body.

That's exactly what happens in places like the Columbia Bar at the mouth of the Columbia River. When there is a strong flood tide and strong storm winds opposed by a strong outflow from the river, that's when the currents and waves are the most dangerous.

--The second thing I wondered about came from the fifth segment where they were talking about how large waves form in the deep ocean in the North Sea. That made me wonder if similar things happen to waves in deep freshwater lakes like Lake Superior, Lake Huron and Lake Michigan.

Could the same set of circumstances that creates the freak waves in the ocean cause large waves in these bodies of water?

Lake Superior 82,000 sq km, 31,698 sq miles in size, is the largest fresh water lake in the world. It is about 350 miles (565 km) long and 160 miles (257 km) at its widest point. The deepest point is 1,332 ft, while the average depth is 500 ft.

Lake Michigan 57,800 sq km, 22,316 sq miles in size, is the largest freshwater lake (totally within) the United States. It is 307 miles (494 km) long and 118 miles (190 km) at its widest point. The deepest point is 925 ft, while the average depth is 279 ft.

Lake Huron 59,600 sq km, 23,011 sq miles in size, is 206 miles (332 km) long and 183 miles (295 km) at its widest point. The deepest point is 750 ft, while the average depth is 195 ft.

I wonder if anyone has tried to transfer the data from the oceans to the lakes.

Thanks for the link to the videos.
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Old 01-08-2013, 04:42 PM   #3
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Greetings,
The same wind against current produces waves effect occurs on the east coast in the Gulf Stream. If there is ANY north aspect to the wind AT ALL you don't go out! Meaning WNW through ENE.
I have heard one theory that suggested a rogue wave sank the Edmund Fitzgerald in Lake Superior.
http://en.wikipedia.org/wiki/Edmund_Fitzgerald
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Old 01-08-2013, 05:15 PM   #4
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Great Lakes you bet. Fitzgerald was the latest. Check out the storm November 1913, 235 sailors lost, 8 ships down on Huron, 2 on Superior with no survivors. Granted perhaps vessels were not as sophisticated as they are today, but Lake Huron, Michigan, Superior can develop 3 to 10 metre seas which are close together. Think heading north out of St Clair River on to the lake with a NW gale wind blowing over a fetch of couple of hundered miles. Lakers can tell you stories which will make your skin crawl.
Summer time is somewhat different, but you must always be on the look-out for weather issues which generate terrible wave action most of which is based on wind fighting current.
A number of neophite pleasure boaters, loopers in perticular have had nasty experiences on the Lakes especally Michigan which offers poor harbour entrances. In some case you are running an inlet especially along the east shore. Another is running up Huron not realizing just how shallow the east shore is. A lot like the New Jersey shore. You must stay beyond at least five off shore and then if you must run for shelter you have a fight into river mouths. Not nice.
A great topic and one we should all take notice of. Bill.
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Old 01-09-2013, 01:03 PM   #5
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Greetings. I posted some pictures on Conditions we might wish to avoid thread. Bill.
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Old 01-09-2013, 02:27 PM   #6
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Greetings,
The same wind against current produces waves effect occurs on the east coast in the Gulf Stream. If there is ANY north aspect to the wind AT ALL you don't go out! Meaning WNW through ENE.
I have heard one theory that suggested a rogue wave sank the Edmund Fitzgerald in Lake Superior.
SS Edmund Fitzgerald - Wikipedia, the free encyclopedia
a strong out going tide with high river flow and a westerly wind makes a nasty bar at several Oregon bars.

I'm wondering if those rouge waves aren't associated with the continental shelf or sea mounts?
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Old 01-09-2013, 02:43 PM   #7
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Greetings,
If one accepts the Peregrine soliton hypothesis it stands that rogue waves can appear in ANY body of fluid, water included due to the double spatio-temporal localization.
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Old 01-09-2013, 03:14 PM   #8
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Greetings,
If one accepts the Peregrine soliton hypothesis it stands that rogue waves can appear in ANY body of fluid, water included due to the double spatio-temporal localization.
No, i think the Buteo jamaicensis effect is more appropriate. It says that the wave height is directly proportional to its direction of travel and the actual vertical and horizontal distance from your position.
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Old 01-09-2013, 03:18 PM   #9
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You guys are too obtuse! This fella makes sense;

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Old 01-09-2013, 04:47 PM   #10
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Does he? He sounded to me like a guy making a presentation in order to justify his salary. I did learn from him, his pictures were very nice and he did purpose a new theory as to the origin of rouge waves. The trouble is as far as i know there are no semi conductors, jetties or lens in the middle of the ocean to create the conditions for the formation of a wave. Need less talk, pretty pictures, and more data to answer this question
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Old 01-09-2013, 06:23 PM   #11
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Greetings,
The same wind against current produces waves effect occurs on the east coast in the Gulf Stream. If there is ANY north aspect to the wind AT ALL you don't go out! Meaning WNW through ENE.
I have heard one theory that suggested a rogue wave sank the Edmund Fitzgerald in Lake Superior.
SS Edmund Fitzgerald - Wikipedia, the free encyclopedia
One theory of the Fitzgerald sinking was that she hit the bottom after going up a very large wave, 30 - 40'. When she struck the bottom it broke her back and that is why she went down so fast.
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Old 01-09-2013, 08:06 PM   #12
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The trouble is as far as i know there are no semi conductors, jetties or lens in the middle of the ocean to create the conditions for the formation of a wave. Need less talk, pretty pictures, and more data to answer this question
It seems plausible to have wave sets converging from two or more directions being refracted by a gyre, or a 'lens' of current changes, which then concentrates whatever combined (freak) waves that form. That's the bit that made sense to me.

Previously I had always imagined wave sets which combined but did not vary in their direction.
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Old 01-09-2013, 08:38 PM   #13
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It seems plausible to have wave sets converging from two or more directions being refracted by a gyre, or a 'lens' of current changes, which then concentrates whatever combined (freak) waves that form.

Previously I had always imagined wave sets which combined but did not vary in their direction. That's the bit that made sense to me.
What you describe we see examples on a small scall f all the time at the entrance to bays where current and waves intersect from diferent directions. When a kid i used to call this troubled water cause it didnt seem to know what to do. If this were the case then these waves would be of short duration and would vanish as fast as they appear.

Your description of same direction different speed waves adding i don''t think works. I think what happens is one wave goes through the other increasing the mass but the height would be close to the same. So you may see every sixth wave or so one with much more volume than the rest. If the angle of attack is diferent for each wave then when they collide they would tend to add for greater height and mass.

just my 2 cents worth i am a dummy on this subject my training was in electrical, environmental engineering and law
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Old 01-09-2013, 08:47 PM   #14
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Greetings,
Mr. 45. Peregrine soliton - Wikipedia, the free encyclopedia Read the link and you may become less of a "dummy" on the subject. "Main Properties" should give you a better understanding.
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Old 01-09-2013, 08:54 PM   #15
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Greetings,
Mr. 45. Peregrine soliton - Wikipedia, the free encyclopedia Read the link and you may become less of a "dummy" on the subject. "Main Properties" should give you a better understanding.
ah, i read soliton as solution. Thank you for getting me on track
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Old 01-09-2013, 08:56 PM   #16
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Waves entering a bay would dissipate as they spread out, as opposed to open ocean waves being concentrated by a gyre 'lens'...right?
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Old 01-09-2013, 09:08 PM   #17
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Waves entering a bay would dissipate as they spread out, as opposed to open ocean waves being concentrated by a gyre 'lens'...right?
wouldnt the jetties, entrance, sea bottom act as a lens? I'm thinking of a bay with a narrow entrance
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Old 01-09-2013, 09:57 PM   #18
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wouldnt the jetties, entrance, sea bottom act as a lens? I'm thinking of a bay with a narrow entrance
Yes, but the waves would be from one direction, and would release their energy along the shore.

Heller's point was that, rarely, current conditions or an ocean gyre could focus the energy of several large wave sets into an area of ocean during a storm. Normally these wave sets would cross each other as they normally do, but under these conditions their energy would be concentrated, making freak waves possible.

That's the way I'm reading it...
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Old 01-09-2013, 11:07 PM   #19
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Yes, but the waves would be from one direction, and would release their energy along the shore.

Heller's point was that, rarely, current conditions or an ocean gyre could focus the energy of several large wave sets into an area of ocean during a storm. Normally these wave sets would cross each other as they normally do, but under these conditions their energy would be concentrated, making freak waves possible.

That's the way I'm reading it...
and that is why i thought of a narrow bay entrance with the jetties which would focus this energy. No open coast line here to dissapate the energy The wave sets approaching from slightley different directions focused by the jetties and lifted by the out going current.
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Old 01-09-2013, 11:38 PM   #20
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and that is why i thought of a narrow bay entrance with the jetties which would focus this energy. No open coast line here to dissapate the energy The wave sets approaching from slightley different directions focused by the jetties and lifted by the out going current.
Oh, now I get what you mean...that would be jumpy for sure!

There is a tear drop shaped island here where the waves cross after being bent by the shoreline. After passing the island they cross at about a 30 degree angle, then bounce off a cliff on the mainland about a mile away which makes for 4 sets of waves all crossing at once. They aren't really waves after that...they just jump into existence, throw their tops away in an explosion of spray, then disappear. Crazy!

Scale our scenarios up to open ocean size and conditions, and it paints an ugly picture.
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