Whoever thinks that the physical world is fully explored
should consider the story of rogue waves.
On January 1, 1995, a huge wave hit an oil platform in the
North Sea near Norway. The platform was equipped with a
measuring and recording device that kept a careful record of
every ocean wave that passed by. It showed that the wave had
reached a height of 61 feet. It was the first measured and
recorded rogue wave.
Enormous waves that sweep the ocean are traditionally called
rogue waves, implying that they are a rarity. Until about ten
years ago, skeptical oceanographers doubted their existence
and tended to lump them together with mermaids and sea
monsters as myths. There were many accounts of sightings of
giant waves over the years, but the scientists were
skeptical. The human imagination embellishes, they said. They
even had mathematical models of the oceans that showed that
giant waves were statistical improbabilities that arise no
more than once every 10,000 years or so.
But research has since found that these giants of the sea are
far more common and destructive than once imagined, prompting
a rush of studies and research projects.
Now one scientist estimated that at any given moment 10 of
the giants are churning through the world's oceans. In size
and reach these waves are quite different from earthquake-
induced tsunamis, which form low, almost invisible mounds at
sea and just gain height when crashing ashore. Rogue waves
seldom, if ever, go close to land.
The large waves rise to heights of at least 25 meters (82
feet) about the size of an eight-story building. Scientists
have calculated their theoretical maximum at 198 feet —
higher than the Statue of Liberty. So far, the large rogues
that have been measured come in at around 100 feet.
Waves of about 6 feet are common everywhere in the ocean,
though waves up to 30 or even 50 feet are considered
unexceptional. As waves gain energy from the wind, they
become steeper and the crests can break into whitecaps.
Over the centuries, many accounts have told of monster waves.
In 1933 in the North Pacific, the US Navy ship Ramapo
encountered a huge wave. The crew estimated its height at 112
feet. In 1966, the Italian cruise ship Michelangelo
was steaming toward New York when a giant wave tore a hole in
its superstructure, smashed heavy glass 80 feet above the
waterline, and killed a crewman and two passengers. Philippe
Lijour, first mate of the oil tanker Esso Languedoc,
described a huge wave that slammed into his ship off the east
coast of South Africa in 1980.
On New Year's Day in 1995, a rock-steady oil platform in the
North Sea produced what was considered the first hard
evidence of a rogue wave. The platform had a special laser
tool designed to measure wave height. During a subsequent
storm, it registered an 84-foot giant.
In February 1995 the cruiser liner Queen Elizabeth II
met a 29-meter 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."
In February 2000, a British oceanographic research vessel
fighting its way through a gale west of Scotland measured
titans of up to 95 feet, "the largest waves ever recorded by
scientific instruments," seven researchers wrote in the
journal Geophysical Research Letters soon after
that.
Once-skeptical scientists were soon holding conferences about
the newly-discovered waves. A large meeting in France in
November 2000 attracted researchers from around the world.
It quickly became apparent that the big waves formed with
some regularity in regions swept by powerful currents: the
Agulhas off South Africa, the Kuroshio off Japan, and the
Gulf Stream off the eastern United States. The Gulf Stream
also flows through the Bermuda Triangle, famous for allegedly
sinking large numbers of ships.
Results from the European Space Agency's (ESA) ERS satellites
helped establish the widespread existence of these rogue
waves. Studying just three weeks of data, scientists
identified more than ten individual giant waves around the
globe above 25 meters (82 feet) in height.
During Hurricane Ivan in September 2004 in the Gulf of
Mexico, six wave-tide gauges of the Naval Research Laboratory
showed waves measuring more than 90 feet from trough to
crest.
But scientists were skeptical and ship designers followed
their recommendations. Ships are designed to withstand a 15
meter wave — much more than was expected. The same
specifications were used to design ocean drilling platforms
and bridges. Now they are obsolete.
Once that they were convinced that they existed, the
scientists quickly came up with explanations for why they
form. Dr. Bengt Fornberg, a mathematician at the University
of Colorado, said the strong ocean currents appeared to focus
waves "like a magnifying glass concentrates sunlight."
"It's the same idea," he told the New York Times.
"There are a few places in the world where there is a regular
current, like a steady magnifying glass. In other places, the
eddies come and go, and that makes the waves less
predictable."
One way that rogue waves apparently form is when the strong
currents meet winds and waves moving in the opposite
direction, he said. The currents focus and concentrate sets
of waves, shortening the distance between them and sending
individual peaks higher. "That," Dr. Fornberg said in an
interview, "makes for hot spots in a fairly predictable
area."
Engineers cannot practically build ships that can withstand
such massive forces as are unleashed by the rogue waves, so
scientists are trying to predict their ocurrence so that they
can be avoided.
Now rogue waves are an accepted scientific fact. But until
1995, even though thousands of ships sailed the seas, they
were considered a myth.
