Re: [Paddlewise] "Sneaker Waves"

From: Craig Jungers <crjungers_at_gmail.com>
Date: Sat, 19 Jan 2008 09:17:00 -0800
On Jan 19, 2008 12:14 AM, Dave Kruger <kdruger_at_pacifier.com> wrote:

>
> You mean "5 seconds" and "14 seconds," yes, Craig?


Oops... yes... seconds not minutes. Ack!

I've always heard sneakers explained as the result of constructive
> interference of two waves from slightly different sources, such that a
> single wave (the result of two combined) "jumps" out of the blue.
>  However,
> there is a more erudite discussion of possible causes here, under "rogue
> waves:"  http://en.wikipedia.org/wiki/Freak_wave


Various groups associated with the ocean have their own interpretations of
sneaker waves (and their own nomenclature, too). A "rogue" wave on the ocean
is very likely a combination of  two (or more) heavy seas plus upwellings or
currents. But that's out in the open ocean and generally in the very rough
open ocean. One of the characteristics of "sneaker" waves is that they are
unnoticed in deep water but potentially catastrophic when the water suddenly
shoals.

But it's possible that a combination of two long-period swells could be the
cause of the single "sneaker" wave. This would help explain the way "sneaker
waves" appear out of the blue in what is a calm ocean (as described by
people who have been snuck-up upon). Long-period swells may not be obvious
on a day with no wind. <http://en.wikipedia.org/wiki/Freak_wave>

>
> Take your pick.  Stuff like this is hard to pin down, scientifically,
> because it is hard to reproduce in a laboratory (wave lab).


I've always been attracted to "non linear science" because there is just so
much of it around. Especially in fluids. Chaotic behavior is always more
interesting to me than predictable behavior. :)

Regardless of the cause, the name, or the science; there are unpredictably
large waves that seem to be associated with long-period (5 seconds and over)
swells in the winter and spring months. If you paddle in shallow watter
exposed to the open ocean you should check for swell periods on the offshore
wave rider buoys and behave in whatever you believe is your best interest.

One question I had is why so many of these "sneaker" wave problems seem to
occur in what is described as calm conditions. Long-period swells must also
occur on days when the wind blows, too. But maybe boaters tend to stay
farther from shoaling water when it's obviously rough.

Didja launch the bartender yet?


Craig Jungers
Moses Lake, WA
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Received on Sat Jan 19 2008 - 09:17:07 PST

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