SQUARE WAVES?

What do you see that is unusual about the above photo?  Those are square waves:

• This scene is off the Isle of Rhé, west coast France, where this natural spectacle occurs regularly.
• They form when two strong weather systems send opposing swells crashing into each other at different angles.

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  They form quickly and vanish.
• But watch out!
• There is hidden danger.
• When square waves occur, they come with powerful currents and high waves, up to 10 feet.
• For swimmers and boaters, you are faced with unexpected forces of nature.
• Swimmers caught in these waves often feel as if they are swimming against two competing currents.
• Boats navigating these waters may be overwhelmed or swamped by the waves themselves.

• 
  So what do you do?
• Simple, leave the water immediately, if you can.
• If caught, signal for help, and stay calm, floating on you back if needed, and try to swim parallel to the shore to escape the currents.

• 
  Square waves have been linked to shipwrecks and drownings worldwide, not only in France.  Danger also lurks in Israel, the South Pacific and Atlantic Ocean.  Watch these waves in the Aegean Sea.  Or, 25 minutes of square waves.

While I'm at this, what about rogue waves?

• Also known as freak...monster...killer...and extreme waves.
• They mostly occur in deep water, far out at sea, and will be a threat to the largest ships.

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  Supposedly occurred on 4August1498, the third voyage of Christopher Columbus, when in the Gulf of Paria off the southern tip of Trinidad, a wave lifted his ships higher than ever experienced, after which the ships dropped into a huge trough.

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  On 28September1853, a huge wave sank the emigrant ship Annie Jane off Barra in the Outer Hebrides, killing 200 people.

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  Cunard's RMSLusitania was struck on 10January1910 during a storm in the Atlantic Ocean west of Ireland, smashing windows in the pilot house 75 feet above the waterline, with water reaching the top of the wheelhouse 80 feet above deck.

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  On 29August1916, a U.S. Navy cruiser USS Memphis was wrecked by three waves up to 70 feet high, generated by a passing hurricane.
• Another Navy ship, the USS Ramapo encountered a huge wave in the Pacific in1934 said to be 112 feet tall.
• The list goes on and on.
• 
  Only anecdotal evidence existed until 1January1995, when scientific measurement confirmed a rogue wave at the Draupner platform in the North Sea.  Watch this video.  This 84 foot wave is considered to be the largest ever, even though historic experiences say they encountered waves exceeding 100 feet.
• Was Hokusai's famous image a rogue wave?

Remember the 2000 movie, The Perfect Storm?  It was based on The 1991 Perfect Storm.

• This deadly nor'easter, also called the Halloween Gale/Storm, was influenced by Hurricane Grace, which sank the Andrea Gail, inspiring the book by Sebastian Junger, leading to the movie.
• A buoy off the Nova Scotia coast reported a wave height of 100.7 feet, the highest recorded in the area.
• Interestingly enough, this storm might have been strengthened by the 1991 eruption of Mount Pinatubo.

• 
  The movie?
• Only got 47/64 scores from Rotten Tomatoes.
• Starred George Clooney and Mark Wahlberg.
• Watch the Giant Wave.  A shorter version.
• In the film the rogue wave was about 100 feet high.

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