I Survived a Whirlpool

I was talking to a man the other day about boats. He was telling me about how he has had many strange experiences out in boats. He told me about a freighter going up the Columbia river (Oregon, USA) This time he was not in the boat but next to it on the shore with his wife. He said that he noticed the freighter going much to fast for the channel it was in, and warned everyone to watch out for the wake.
When the wake came to the shore it was enough to send his boat and all of the picnic equipment into the trees!
Of all his strange experiences in the rivers of Oregon, nothing had prepared him for what he was about to go through on a very wide stretch of the Columbia river.
He and his wife were moving along at a good pace in his 15 foot skimmer one day when he looked up at the clouds and didn't like what he saw. He said the clouds had that "strange" look to them. "When you see clouds like that, it's time to get out of the river." He said. They kept on going at a good, steady speed, when all of a sudden, he looked in front of him and saw no water at all, no river. He quickly looked around to try to figure out what was going on. He then realized that the boat had fallen into a giant "hole" in the nearly mile-wide river. He went on to describe what can only be explained as a giant whirlpool. He said it was at least 100 yards across, and thirty to forty feet deep with thirty degree slanted walls. In the blink of an eye he decided the only way to get out of this thing was to head directly for the center or bottom of the whirlpool. He said: "The walls of this thing were so steep, I knew there was only one way to go, down one side and up the other."
He never was able to find out what it was. No one he had ever talked before or since that day can give him an explanation.
A thorough internet search has yielded no information concerning whirlpools.
I have heard that they sometimes appear that big in the ocean during certain rare types of storms. But none of this can be confirmed from a reputable source.
If any of you reading this can tell me anything about whirlpools, please send me mail! webmaster@thestrangedotcom.com

There are however, many whirlpools in "mythology" I found and article that tries to explain the scientific fact behind the stories of whirlpools, at least as it pertains to the North Atlantic.
Here is an excerpt form that article.

The "arctic mirage" is as typical of high-latitude
regions as the "desert mirage" is of desert areas; in Greenland,
it occurs on as many as 20 days out of 30 during some months.
      The mirages occur when the air immediately above the Earth's
surface is colder than the air at the higher elevations. Such an
increase of temperature with elevation is known as a temperature
inversion. Under such conditions, light rays do not travel in
straight lines, but are bent (refracted) around the curvature of
the Earth. The stronger the temperature inversion, the greater
the curvature of the light rays. When ray curvature equals Earth
curvature, it creates the optical illusion that the earth is
flat. In more extreme cases of temperature inversion, which are
by no means uncommon, the Earth's surface appears saucer-shaped,
and objects which are normally out of sight--coastlines, for
example--are raised into view.
The Norse concept of the world included dangerous phenomena
that existed at the edges of their world. Their sagas tell of
the dreaded hafgerdingar (sea fences) which were capable of
capturing ships and sending them down to certain destruction.
Medieval mariners reported that the waters between Europe and
Greenland were filled with treacherous whirlpools, vortices, or
sea fences.
      Various explanations are advanced for this preoccupation
with the much-feared hafgerdingar. Peter Frederik Suhm's sugges-
tion in 1790--that the legends were based on a powerful eddy, or
Maelstrom, near the Lofoten Islands--is no more satisfactory than
Scylla and Charybdis. The Lofoten Islands lay on no shipping
lane and, therefore, came under the purview of few, if any,
mariners.
      Theories about the hafgerdingar based on possible encounters
with submarine earthquakes do not yield a satisfactory explana-
tion either. Typical of such events is the fact that, except in
the immediate vicinity, the disturbance of the sea surface is
minimal. The odds against ships being over the epicenter of an
earthquake with sufficient frequency for the experience to become
the basis of a firmly established legend are too great to be
taken seriously.
      Nor can the legendary hafgerdingar be written off as pure
myth. The 13th-century King's Mirror speaks of hafgerdingar, but
also presents sober, amazingly accurate accounts of the large
marine mammals found in the North Atlantic, and the nature of the
sea ice and its drift. It would appear irresponsible to accept
that part which conforms to out own knowledge, and dismiss the
rest as the product of fear-ridden imagination. There must be an
element of truth to these legends.
      The hafgerdingar did exist, and still do--albeit only as
optical illusions. Like the hillingar, they are an arctic mirage
caused by temperature inversion and increased atmospheric refrac-
tion. To an observer, the appearance of the foreground remains
normal, but the horizon becomes elevated, and "walls" or
"barriers" appear in the distance. It is simply an exaggerated
case of the saucer-shaped Earth: The apparent upward slope of
the sea near the horizon is foreshortened, and the actual horizon
appears as a wall only a few kilometers distant.
      At sea, in the absence of normal terrestrial aids to orien-
tation, the visual impact of the hafgerdingar must have been
frightening indeed. The mariner would have received an almost
overwhelming impression of being below the lip of a wide vortex,
the waters poised as if ready to engulf him. The presence of
another vessel within the field of view would only strengthen the
impression: Even at distances of only a few kilometers, the
waters beyond would loom much higher than the neighboring vessel.
In medieval times, the high losses among trading ships in the
North Atlantic could easily have kept alive the belief that such
a vortex had drawn the ships down to destruction.