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Old 20-08-2008, 07:05   #1
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92 ft + WAVES

Found this yesterday when I was checking on Fay.

http://www.livescience.com/environme...804_waves.html

I've never lived thru a hurricane, so I have no idea what those of you on the other coast go thru. What happens to all that wave height when they reach shore? These sensors were under sitting at 200-300 feet deep! As they get closer to shore do they just fall on themselves sooner?
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Old 20-08-2008, 07:35   #2
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Originally Posted by Minggat View Post
Found this yesterday when I was checking on Fay.

http://www.livescience.com/environme...804_waves.html

I've never lived thru a hurricane, so I have no idea what those of you on the other coast go thru. What happens to all that wave height when they reach shore? These sensors were under sitting at 200-300 feet deep! As they get closer to shore do they just fall on themselves sooner?
My theory/guess is that there isn't usually enough fetch usually in a hurricane to produce these wave heights where the water meets the land. Remember... a hurricane, although large, is a local disturbance.

The average diameter of a hurricane's winds (the hurricane force part) is only 100 miles. So... taking into account that the winds are in a vortex pattern, there is probably only 50 miles of fetch under hurricane force winds, resulting in shorter seas than one might expect. (Neglecting the problem of the storm surge)

Larger waves are created by strong winds blowing across long stretches of open water.

Well, that's my BS theory, anyway! ha ha
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Old 20-08-2008, 07:58   #3
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It is not really the height of the wave that is a problem.

The real problem is how steep that wave is, and this is a feature of distance between wave crests. Wave heights in the deep atlantic that appear to be of no real problem, become a major danger when they hit the continental shelf and the wave steepens.
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Old 20-08-2008, 08:01   #4
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This is interesting.

Fetch- and Depth-Limited Wave Calculations

Check it out :

http://woodshole.er.usgs.gov/staffpa...unSPMWave.html
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Old 20-08-2008, 09:21   #5
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HURRICANE - GENERATED OCEAN WAVES
http://www.waveworkshop.org/9thWaves...s/Xu_Fumin.pdf

HURRICANE-GENERATED WIND-WAVE RESEARCH AT NOAA/NCEP
http://www.waveworkshop.org/8thWaves/Papers/G3.pdf


Numerical Simulation of Sea Surface Directional Wave Spectra under Hurricane
Wind Forcing
http://neptune.gsfc.nasa.gov/publica...Simulation.pdf
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Old 22-08-2008, 21:14   #6
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Those are some pretty big waves. Just 20 feet is high, and that's more than eight times bigger!
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Old 22-08-2008, 21:30   #7
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When one describes a wave one really needs to describe not only its height but its period. The shorter the wave period, the sooner the energy is dissipated through breaking at the top. Its the longer period waves that are such a danger when they hit a coastline. At sea, they are hardly a factor. Its the short period waves that can make life miserable or dangerous.
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Old 23-08-2008, 01:20   #8
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Totally agree - in fact that is what I said at "3" above, but your words are better
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