Sunday, April 17, 2011

Interference Patterns

The other day, I watched a Smithsonian Channel show about the sinking of the Edmund Fitzgerald. The Great Lakes freighter, heavily laden with iron ore, was overtaken by a November storm on the eastern side of Lake Superior in 1975. All her crew were lost.
The official report blamed human error -- latches that weren't closed well. Later scientists weren't so sure. The Smithsonian show suggests that she was struck by a rogue wave, broke apart, and sank in two pieces.

For a long time, the idea of "rogue waves" was dismissed as legend. Not anymore. Simply put, a rogue wave is a large wave that comes seemingly from nowhere. It happens without warning, and can toss a 26,000-ton ship around like styrofoam. Where do they come from? A leading theory is "diffractive focusing" -- regular waves coming from different directions that meet up briefly. If their waves are in phase -- cresting in the same place at the same time -- they multiply. The result is, well, a nightmare.

So what's this have to do with a Flotsam Diarist? Well, as winter has dragged into spring, I've spent some days just lingering, watching Bay View's waves. And I noticed, they're not all coming from one place. In fact, they roll in from the east-northeast & the east-southeast, bashing into each other near the shore.
My daughter patiently awaiting a ditch-filler
That, and the story of the Edmund Fitzgerald, got me thinking. I hadn't really thought about the ocean being made up of different energies, propagating from many different directions. But once I knew what to look for, I couldn't miss it. Turns out, all that interference may be causing Bay View's weird cusps -- the ridges that can be seen running up and down the shore.
Crest, trough, crest, trough, crest...
After all, a beach is just the result of the energy of the ocean. The ocean creates it, sculpts it, erodes it. And that energy doesn't just move sand and shell. It moves kelp and plastic too. If the energy hitting a shore has highs and lows, does that say anything about how -- and where -- one might find the flotsam it carries?

Worth a thought.
I'll never look at a ripple the same way again.

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