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View Full Version : Three Fingered Jack, Oregon Activity



dgavin
2012-Aug-11, 01:57 PM
Had a major glacial lake dam broke, with a flood and debris flows.

Three Fingered Jack is an acient volcano, that been so erroded that it doesn't even look like our other conical mountains.


On the weekend of July 28, hikers in Canyon Creek Meadows near Three Fingered
Jack (central Oregon Cascades) were surprised to find boulders and mud coating
the west end of the meadow. The deposits are from a recent debris flow caused by
a partial breach of a lake dammed by a young glacial moraine at the snout of
tiny “Jack Glacier.” The sudden outflow from the lake incorporated rocks, sand,
and mud that was deposited in a bouldery fan at the foot of the moraine with
muddy water flooding the meadow and flowing into Canyon Creek. The trigger for
the breach is not yet known.

Image http://volcanoes.usgs.gov/vsc/images/image_mngr/400-499/img442.jpg