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Are freak waves more likely in certain areas or
situations? Freak waves can occur in any ocean around the world, but there
are certain areas where freak waves are more likely:
- South Africa -
freak waves occur off the east coast of South
Africa when there is a strong wind blowing in
the opposite direction to the strong Agulhas
Current. (The South African Weather Service now
gives freak wave warnings.)
- Norway - the
coast of Norway is another hotspot because the
sea bottom can focus waves together to form
monsters - in bad weather the shipping route is
altered to avoid these areas.
- Pacific -
certain areas of the Pacific are also notorious
for freak waves, when typhoons whip waves up to
huge heights.
WALL OF WATER.
Rogue waves, such as this
20-meter-tall monster encountered in
1986 by the SS
Spray in the Atlantic's Gulf
Stream, can appear even in calm
seas.
Can
scientists predict freak waves?
At the moment the
only place where freak waves can be predicted is
South Africa. There is no way of knowing when or
where a freak wave will hit anywhere else.
Scientists at the UK Meteorological Office are
working on the problem and think they might have a
solution. If Al Osborne's non-linear Schrodinger
theory is right, then freak waves should occur
whenever there is a peak in the energy spectrum (ie
when a lot of energy is crammed into waves of a
specific wavelength). So the Met Office has been
looking back at recorded cases of freak waves, like
the 1995 Draupner wave, to see if the spectrum is
peaked. So far the theory holds up and they hope to
come up with a practical way to warn ships about
freak waves in the next couple of years.
Are
freak waves the same as tsunamis or tidal waves?
No. Tsunamis and
tidal waves are extremely rare events caused when
either an earthquake or landslide displaces a large
volume of water creating a single large wave. Freak
waves are occurring far more regularly and seem to
be a fundamental property of the sea.
NOAA
Ship Discoverer gets pounded by monster wave in the
Bering Sea. This picture was taken in 1979.
Because Rogue Killer Waves strike without warning,
photos of these monster waves are extremely rare.
How
many ships have been sunk by freak waves?
No one knows how
many ships have been hit or sunk by freak waves. A
ship is lost at sea every week, but there is often
surprisingly little detail as to why or what
happened. Usually poor maintenance or human error is
blamed, but it is likely that at least some of these
losses may be related to freak waves.
Do
ships need to be redesigned?
The risk from freak
waves in uncertain. Ships are built assuming that in
their 20 year lifespan there is no risk from freak
waves. The new evidence suggests that the risk is
higher than originally thought, but the data are far
from conclusive. Until the risk is fully assessed,
international maritime organizations and
classification societies can't know what (if any)
changes need to be made to ship specifications.
Should I be worried about going to sea?
If you weren't
worried before, you shouldn't be worried now -
according to Department of Transport statistics it's
over ten times safer to travel by sea than it is to
cross the road.
Source BBC
Killer Monster Wave Come Close To Land Too
DESPERATE RACE FOR
SURVIVAL / RIDING FOR THEIR LIVES: Two water safety
patrollers on Jet Skis at Maverick's reef turned
around to see deadly 100-foot waves crashing toward
them. They had just seconds to figure out how to
stay alive.
The waves crashing
into Maverick's reef towered twice as tall as they
typically do at the annual surf contest there. Many
of the world's top surfers had been driven from the
sea, leaving safety patrollers Shawn Alladio and
Jonathan "JC" Cahill alone on their Jet Skis on the
roiling waters.
It was Nov. 21, 2001, a day that would become known
as One-Hundred-Foot Wednesday in the lore of
Maverick's wave-riders -- who now await the call for
this year's event.
 As monstrous sets of waves loomed, Alladio and
Cahill were forced to make a life-or-death choice in
a matter of seconds: Should they try to run from the
onrushing mountains of water or charge at them,
trusting their skills, instincts and machines to
surmount the challenge?
"That first wave was so huge, it was appalling,"
Alladio, a veteran watercraft racer and mother,
recalled. "To the north I could see this huge hole
of the barrel, like a tunnel in a cliff, sweeping
down on us, roaring like a jet engine. I could see
JC out of the corner of my left eye, and I remember
thinking: 'I've got to survive, for my daughter. And
he can't die; how could I ever explain that to his
parents? So Jonathan, we can't make a mistake!' "
In midwinter, the North Pacific can be a vast
cauldron of swirling winds and colliding seas, and
the big-wave surfers obsessively scrutinize
satellite data and buoy reports as organizers of the
Maverick's Surf Contest look for the most
predictable series of big waves to stage the event.
On that fabled Wednesday five years ago, two dozen
surfers got all they could ask for -- and much more
-- as the swells rising off the San Mateo County
coast soared off the charts of the known.
Source:
San Francisco Chronicle 
Carnival Cruises - The
Fun Cruises!
In 2008, a cargo ship
was grounded off Blackpool, England after being hit
by a freak wave
Scientists in the US have made a major advance in
their understanding of so-called freak waves.
These monster waves present a major risk to ships
and offshore platforms.
A computer simulation developed by oceanographers in
the US could help locate where and when these
"rogue" phenomena are most likely to occur.
The theoretical study shows that coastal areas with
variations in water depth and strong currents are
hot spots for freak waves.
The history of seafaring is littered with tales of
rogue waves capable of rending ships asunder.
A freak wave is one that measures roughly three
times higher than other swells on the sea at any one
time. These phenomena can measure up to 18m (60ft) -
the height of a six-storey building.
The new computer simulation was developed by Tim
Janssen of San Francisco State University (SFSU) and
Thomas HC Herbers of the Naval Postgraduate School
in Monterey, California. Their findings are
published in the Journal of Physical Oceanography.
Focal zone
Sandbanks and strong currents may cause waves to
change direction and speed. This concentrates wave
energy into a single point, which oceanographers
call a "wave focal zone". This zone is
like a burning glass, Dr Janssen explained, where
the light comes in and focuses all the energy on a
single point, forming a hot spot. The
same happens when a wave travels over, for example,
a sandbank, or over a current. The energy is being
focused on to a single point.
The researchers found these hot spots were much more
likely to drive the formation of extreme waves.
"In a normal wave field, on average, roughly three
waves in every 10,000 are extreme waves," Dr Janssen
explained. "In a focal zone, this number could
increase to about three in every 1,000 waves."
The scientists fed data on real waves into their
computer model. Then, they repeated a single
experiment over and over, each time using different
data. The SFSU oceanographer said he next
hoped to go to known freak wave hotspots such as the
Cortez Banks on the coast of California to test
whether his simulations held true. "What's
really important about this research, is that it is
easy to validate. We have a theory now, a
prediction, and we can go to areas and actually
measure whether this happens or not," he told BBC
News.
Vital
knowledge
Understanding where and when freak waves are most
likely to occur could assist shipping and navigation
in coastal areas. The knowledge could be used
for marine weather forecasts and could also inform
the design of offshore platforms. "If
you know that a certain area is very prone to freak
waves, then you might wish to stay away from it," Dr
Janssen said. "Anybody out in the ocean would
like to [have this information]." However, Dr
Janssen was keen to stress that the study is
theoretical.
"We have tried to be as realistic as we could, but
we are a long way away from making a prediction
solid enough for people to actually use. However, it
might be something to work towards," he said.
Dr Janssen added that the word "freak wave" was
unfortunate, as it suggests these types of wave are
unexpected. But, he explained, the random nature of
ocean waves means that any size of wave can happen
at any time.
Source:
BBC |
