The science and history of rogue waves, part one

In what could prove to be a huge step forward in predicting how rogue waves are formed, and thus a tool for saving lives at sea, researchers at MIT have found a way to give 2 to 3 minutes warning of an incoming rogue wave.

I know it probably sounds stupid, but it’s hard for me to explain how excited I am about this research.  So much so that I am tempted to go speak with the researchers sometime (living in Cambridge does have its advantages).  But to understand why I am geeking out about this, it might help for me to go into some detail about what we know about rogue waves, and how they have affected ships at sea, as well as oil rigs, lighthouses, and coastlines.  This is one of those times that my love of history (especially maritime history) and my love of science come together.

Rogue waves (also sometimes known as monster waves, freak waves, killer waves, etc.) are, essentially, abnormally large waves that appear without warning.  The official definition of a rogue wave according to oceanographers is a wave that is at least twice the significant wave height.  They are not the same as tsunamis, in that tsunamis are generated by an event in which a large amount of water is suddenly displaced, such as an earthquake or an impact event.  While tsunamis are generally small out in the deep ocean and get larger as they approach land (except for megatsunamis, which are a whole other story), rogue waves are generally found in the open ocean. They are generally considered to be atypical for a given sea state.  In other words, most waves you encounter are 10 to 12 feet, and suddenly here’s one three or four times that size.  Or worse, you are in calm seas and suddenly a large wave hits from seemingly out of nowhere.  So rogue waves are considered dangerous not only for their size, but because they are wildly unpredictable and by nature unexpected.

As a society, we seem to be more inclined to believe outrageous theories about the Bermuda Triangle, UFOs, wormholes, or other silliness than accept the probability that every once in a while, circumstances produce waves that are far outside the norm of experience for anyone, even experienced professional sailors.  I don’t know why.  Maybe it’s because one explanation requires, if not an understanding of the science, at least a willingness to believe that science can provide a valid explanation.

For a very, very long time, rogue waves were considered to be a tale told by sailors, like mermaids or sea monsters.  Scientists in the early 19th century considered a height of  30 feet or so to be the maximum that a wave could ever reach.  For a long time, U.S. Navy ships were designed with the idea that no waves they encountered would ever be larger than 70 feet.   Most oil rigs were generally designed to withstand waves of similar height, with such waves thought to occur once in 10,000 years.  With such enormous waves thought to be so rare, ships and ocean platforms designed with those waves in mind should have been quite safe.  Sure, there were stories from sailors who said they encountered much larger waves, but science did not take them seriously, and neither did shipbuilders.

But over time, the stories about large rogue waves have been slowly accumulating.  Some are quite well-documented.  One of the most well-known incidents, especially among students of the Second World War, is what happened to the giant liner RMS Queen Mary in mid-December, 1942, during an ocean storm in the North Atlantic. The ship was carrying over 16,000 American troops to Britain.  Author Bruce Parker describes the incident in great detail in his book The Power of the Sea: Tsunamis, Storm Surges, Rogue Waves, and Our Quest to Predict Disasters.

Seven hundred miles from Scotland, the Queen Mary suddenly fell into an almost bottomless trough and was then broadsided on her port side by a monstrous wave crest that was at least twice the height of any she had encountered.  This mountain of water shattered windows on the bridge, ninety-five feet above the waterline.  It tore away all the lifeboats on the port side of the top deck.  It broke through portholes, sending water rushing into hundreds of cabins.  But most seriously, the weight of this stupendous wave, thousands of tons of water, slowly pushed the Queen Mary over farther than she had ever rolled before.  The lifeboats on the starboard side swung down with the ship and almost touched the sea.

Afterwards, it was determined that the ship had heeled over 52 degrees, so much that many soldiers were thrown out of their bunks and onto the walls of their cabins.  If the ship had gone over another 3 degrees, she probably would not have been able to recover, and would have capsized.  It is believed that this incident inspired Paul Gallico to write his novel The Poseidon Adventure, on which several movies have been based.

Anyway, more to follow, when I talk about how much we have learned in recent decades.

-Geoff