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Posted at 11:15 AM ET, 11/21/2008

Rogue Waves: They're Real, & They're Spectacular

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I recently learned I might serve this spring as a subject expert aboard a cruise ship crossing the Atlantic, as part of an "enrichment program" that provides passengers the opportunity to interact with experts in various fields. I've been identified as an individual who will address "Everything You Wanted to Know about the Weather, Sea and Sky - and Then Some!"

Sounds great. My only real concern was whether I might get sea sick, having never been on an ocean cruise. But then I began thinking about a recent presentation (ppt) on "rouge waves" given by Linwood Vincent, of the U.S. Office of Naval Research, at a meeting of the DC Chapter of the American Meteorological Society. As I thought about Vincent's nightmarish stories and pictures, I worried that sea sickness could be the least of my problems, even if the odds of encountering a rogue wave are extremely small.

Keep reading for more on these monstrous waves...

Technically, rogue waves, sometimes referred to as "freak waves," are defined as waves whose height from wave crest (highest point) to wave trough (lowest point) is more than twice the average height of the largest one-third of waves in a set of measured waves. More simply, as Vincent explained, they are essentially "big waves relative to what you expect to be there."

As described nicely by an article in the New York Times, the two most likely explanations for the occurrence of rogue waves are when smaller waves merge to form large waves, and when storm-generated waves crash into ocean currents coming from the opposite direction.

Vincent cites the example of an oil platform in the North Sea that was experiencing rough but reasonable waves of 13 to 26 feet during a storm on New Year's Day, 1995. Suddenly, seemingly out of nowhere, the platform was hit and extensively damaged by a monstrous wave that instruments measured at more than 80 feet in height (the so-called "Draupner Wave").

Want to go even bigger? In February 2000, scientific instruments onboard a British research west of Scotland measured waves up to 95 feet. More recent (but perhaps somewhat less reliable) observations have recorded wave heights up to 110 feet, about the same height as the Statue of Liberty. Just as important as height is that rogue waves are usually extremely steep. Plowing into one is like hitting a nearly vertical wall of water. If a vessel is lucky enough to survive the initial impact, then coming over the crest is like riding down the steepest incline of the world's tallest roller coaster.

And, by the way, I've never been so scared as my first ride on a roller coaster not too many years ago -- and have not been on one since.

For centuries, these enormous waves had been dismissed as myths. But scientists now recognize these giant wallops of water are far more common and destructive than once imagined. According to Vincent, freak waves are suspected of sinking at least dozens of large ships, including supertankers, while taking hundreds of lives. Freak waves are known to occur in the Great Lakes as well as the oceans. It is believed that just such a wave contributed to the sinking of the freighter SS Edmund_Fitzgerald in May 1975 on Lake Superior. All 29 hands perished in this most famous of Great Lakes disasters.

Cruise liners, at least in recent times, have been more lucky -- if you can call it that -- in their close encounters with rogue waves. In February 1995, the Queen Elizabeth II was slammed by a 95-foot-high wave in the North Atlantic. Captain Ronald Warwick described it as "a great wall of water... it looked as if we were going into the White Cliffs of Dover." But the ship survived with some passengers suffering relatively minor injuries. In April 2005 off the coast of Georgia, the Norwegian Dawn, a 965-foot ocean liner, was struck by a rogue wave estimated at 70 feet high. The wave smashed windows, sent furniture flying, injured four passengers and, not surprisingly, instilled widespread fear and panic.

And the accounts above are only a sampling of the many that have been reported. For example, see: here and here.

The only video of an actual encounter with a rogue wave I'm aware of is the amazing encounter of a 100-foot fishing boat, which was shot for the Discovery Channel's program, "The Deadliest Catch."

As for that gig on the cruise ship, I'll take the advice of my 4-year-old granddaughter: "Don't be scared, Pop-Pop. I didn't get scared when we went sledding last year down the big hill." How could I not go after that kind pep talk? And besides, running into a rogue wave is even less likely than being swept up by a tornado or hit by lightning. But I'll be sure to pack the sea-sickness pills, and probably not mention rogue waves to the passengers.

By  |  11:15 AM ET, 11/21/2008

Categories:  Science, Science

 
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