On Wed, 02 May 2007 13:07:50 -0400, Wayne.B
wrote:

On 2 May 2007 09:35:01 -0700, Chuck Gould
wrote:

What do oceanologists say about the generation of a rogue wave?
Anybody know? When conditions are fairly benign, say maybe 8-10 foot
swells, what oddball force kicks up a single, 40-foot, steep and
cresting wave?

I'm not an oceanologist but I think I understand the process. On the
open ocean 10 to 12 foot waves are not at all uncommon, especially if
an active weather front has passed through recently. These waves are
fairly benign, i.e., they are not usually steep or breaking in deep
water. They do travel a long way before dissipating however. As a
result it is not uncommon to have 2 or 3 different wave trains passing
through an area at the same time, frequently from different
directions. Peak wave height then becomes a statistical probability
excercise of computing the chances that these multiple wave trains
will all happen to coincide at a given time and place. When that
happens, either a much larger than average wave is created, or just as
probable, a deep hole. Either the wave or hole is an anomaly which
gravity will try to destroy as quickly as possible with
collapsing/breaking water.

Discovery Channel had a great episode on these waves - it was quite
interesting and made the case for several causes, but the most common
apparently is phase coupling - where a group of waves combine to
create monster waves.

According the satellite surveillance (I believe it's called the ESKA
satellite), they are very common sometimes doubling or tripling the
height of the surrounding waves, but they are rare to encounter.
Thanks to some computer modeling, waves, in theory, can reach as high
as 120 feet peak-to-peak. There is some speculation that these types
of waves, in particular in storm fronts, may actually exist. The
satellite tracked one which was 90 feet high and lasted for something
like five minutes.

I'm sure our friend from down under didn't watch that one though -
went against everything she postulated. :)