For centuries sailors have been telling stories of encountering monstrous ocean waves which tower over one hundred feet in the air and toss ships about like corks. Historically oceanographers have discounted these reports as tall tales-- the embellished stories of mariners with too much time at sea. But in the last eleven years scientists have discovered strong evidence indicating that such massive rogue waves do exist. The phenomenon has become the subject of recent scientific study, but their origin remains a mystery of the deep.
About one ship is lost every week in the world's oceans, mostly due to poor seamanship or severe weather. But it now seems likely that at least a small percentage of sea disappearances are due to encounters with these destructive waves. Over the years experienced captains have made very credible reports of meeting behemoth waves which appear spontaneously, cause extensive damage to their ships, and shrug back into the sea just as mysteriously as they had appeared. One account describes the appearance of a giant wave trough which onlookers likened to a "hole in the sea", followed by a twelve-story-tall "wall of water." To further compound the mystery, some such waves have been said to appear mid-ocean, and often in calm weather.
On the open sea, waves can commonly reach seven meters in height; or even up to fifteen in extreme weather. In contrast, some reported rogue waves have exceeded thirty meters in height. Curiously, rogue waves are often seen traveling against the prevailing current and wave directions; and unlike a tsunami, rogue waves are localized and very short-lived. Most modern merchant vessels are designed to withstand about fifteen tons of pressure per square meter, but these unusual waves exert a pressure of about one hundred tons per square meter. Needless to say, a rogue wave means big trouble for any ship it meets.
Encounters with rogue waves have been rare but memorable. In 1933 in the North Pacific, the US Navy transport USS Ramapo triangulated a rogue wave at thirty-four meters in height. In 1942, the RMS Queen Mary was transporting 15,000 US troops to Europe when it was hit by a twenty-three meter wave and nearly capsized. The giant vessel listed by about 52 degrees due to the impact, after which it slowly righted itself.
In 1978, the 37,000-ton MS Munchen radioed a garbled distress call from the mid-Atlantic. When rescuers arrived, they found only "a few bits of wreckage," including an unlaunched lifeboat with one of its attachment pins "twisted as though hit by an extreme force." It is now believed that a rogue wave hit the ship, causing it to capsize and sink. No survivors were ever found.
In 1996, the Queen Elizabeth 2 encountered a rogue wave of twenty-nine meters, which the Captain said "came out of the darkness" and "looked like the White Cliffs of Dover." London newspapers said that the captain situated the vessel to "surf" the wave to avoid being sunk.
Despite these and other encounters with rogue waves, scientists long rejected such claims as unlikely. Anecdotal evidence is often unreliable, so researchers used computer modelling to predict the likelihood of such massive waves. Oceanographers' findings indicated that waves higher than fifteen meters were probably very rare events, occurring perhaps once in 10,000 years. That all changed in 1995 when a freak wave hit the Draupner North Sea oil platform. The oil rig swayed a little, suffering minor damage, but its onboard measuring equipment successfully recorded the wave height at nineteen meters.
More recently, satellite photos and radar imagery have documented the existence of numerous rogue waves, and it turns out that they are far more common than previously thought. During a three-week study in 2001, radar scanning detected ten monster waves in a 1.5 million square kilometer area. Satellites and direct observations have also established that rogue waves can happen anywhere, but they are most numerous in the North Atlantic and off the western shore of South Africa. In spite of their frequency, monster waves rarely meet with sea vessels because they are so short-lived.
The cause of rogue waves is still an area of active research. One theory under investigation cites "constructive interference," which is a result of several smaller waves overlapping in phase, combining to produce one massive wave. Another working hypothesis is based on the "non-linear Schrödinger effect," in which energy is "soaked up" from neighboring waves to create a monster wave. Still other researchers are looking into the possibility that wave energy is being focused by the surrounding environments, or that wind action on the surface is amplifying existing effects.
Science is necessarily skeptical of things which are beyond our observation, but now that rogue waves are a measurable phenomenon they have been officially upgraded from legend to reality. This recent finding is very telling about how little we really know about our world's oceans, and how many secrets the sea must still hold.