Planet
Waves
Contents:
Intro
Tsunamis
Vs Giant Waves
Other
introspective pages
Natural
or man made disasters
A
change in Attitude
Katrina
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Rogue
Waves
"Water,
water, everywhere, nor any drop to drink."
"Rime of the Ancient Mariner,"
Samuel Coleridge
Intro
Although
of different sources Tunamis and Rogue, or Giant, waves (aka Freak,
Monster and Maverick waves) have the same devastating power. The principal
difference between them is that rogue waves rarely hit land and when
they do they invariably get classed as Tsunamis without further distinction.
Rogue waves generally go unnoticed by the general public...except for
the occasional extraordinary stories told by people who have experienced
such phenomena*...
(* In February 1995 the cruiser liner Queen Elizabeth II met a 29-metre high
rogue wave during a hurricane in the North Atlantic that Captain Ronald Warwick
described as "a great wall of water… it looked as if we were going
into the White Cliffs of Dover.")
Cargo
ships, tankers, containers and passenger ships where disappearing for no
apparent reason leaving little or no trace. Ships had been disappearing in
mysterious ways ever since history has been recorded and until recently such
disappearances where considered nautical myth of legendary origins.
Rogue
waves have, however, recently become the subject of some very serious study.
Preliminary results diagnosed the cause and Merchant companies the world
over were soon aware of the results of the studies...the news was alarming.
The
cause for the alarm? Scientists had diagnosed the reason for the loss of
the ships, normally built to resist "normal" sized storm waves
(± 15 metres), as being the result of rogue waves of exceptional size
and force, often as much twice or three times the height of the average storm
wave.
The news
was bad. Merchant companies, and even countries, were confronted with the
fact that their ships, super tankers of more than 250 000 tonnes and container
ships of 200 metres long, were not as invulnerable as they believed. The
prospect of having to pay billions in rebuilding their merchant fleet caused
panic however, better news was soon to follow.
Tsunamis Vs Giant
Rogue waves
Contrary to Tsunamis,
that regularly make the news** and are attributed notably to earthquakes
or underwater landslides, Rogue Waves are generally created when certain,
very specific, marine and submarine conditions are met, ex:
1- when 2 waves of lesser power and dimensions collide in open sea cause
a compression that has no issue but upwards
2-
when underwater currents clash and/or prevailing winds change direction
and/or tides.
(** Dec 26 2004. A giant Tsunami hit vast regions of South East Asia
and caused the loss of thousands of lifes)
One
famous example of a zone where Rogue waves are frequent is just off the the
coast of South Africa where the "Agulhas
Current" runs North East/South West down from the Indian Ocean.
This current is a warm water current and when it is met with an ascending
cold water current, originating from the Southern Atlantic/Antarctic ocean
conditions are ideal for the creation of Monster Rogue waves.
Monster
Rogue Waves are, for the time being, so unforeseeable and so strong
(100 tons/M²)that a 30 metre wave can sink a ±250 000 ton
tanker in a flash, knocking holes straight through a ship's hull like
a battering ram. Monster Rogue Waves can
also seriously damage a ± 250 Metre high North Sea offshore rig,
the equivalent of a seventy story skyscraper!
Once considered freak events,
the acceleration in communications and the access to satellite images
from agencies, such as the ESA,
is proving that Rogue waves are in fact quite common. Scientists are
able to establish risk zones around the globe where such phenomena frequently
happen. As a result Merchant companies are now able to reroot their
shipping to contour these regions, save billions in insurance and avoid
having to reconstruct their fleet.
To
be continued...
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