22 April 2014

[pdx] Come To The River: See the Missoula Floods Without Getting Wet Or Killed

Spend any time looking into Oregon prehistory, you'll find out about the Missoula Floods. They went a long way toward making the Willamette Valley the way it is.

Goes like this: between 13 and 15 kiloyears ago, when the last Ice Age was waning, a glacial dam across the Clark Fork created a great sprawling lake in the mountains of what is today western Montana called Lake Missoula. Sources I've read say it held at least 500 cubic miles worth of water. Glaciers being what they are during a period of melting about twice every century, that dam would give way, and the waters would gush across what is now eastern Washington, scour out the Columbia Gorge, and back up into the Willamette Valley, making great temporary lakes along the way (the filling of the Valley was called Lake Allison).

This happened dozens of times over that 2,000 year span. And, as a result, we have thick, rich, beautiful agricultural soil here in the Willamette, while Washington just gets the channeled scablands. In as much as Washington also gets the hot tech companies and professional baseball, I think it about evens.

Along the esplanade, alongside OMSI, is the above plaque. Embiggening it should give one enough of a view of the graphic to impress. The artist's conception is, of course, of the Missoula flood at its greatest height, if Portland had been there at the time.

The floods rose to a depth of more than 400 feet, it's estimated. How deep is that? Well, a picture is one thing, a bit of reality, another. The above plaque is set into a worderfully-designed kiosk-like object, as seen here:

Those two tubes, on on each side, are sights. The end is specially covered so that, sighting down them, you'll see just what would be left above the waves. And just what is that?

The upper 6 or so floors of the Wells Fargo Tower, and just a few condo units at the KOIN Center.

Oregon … things do look different here.

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