Tuesday, December 9, 2014

Geo 730: December 9, Day 708: Big Berm

Zooming into the leftish-center of yesterday's photo, you can see the large berm formed, I'm supposing, as the lahar mounded up over the river bank as it swung around that bend. It's far enough distant, and I'm uncertain enough about the size of the trees, that I can't even guess at the size of that bank. But it's clearly pretty big.

I get the sense here that much of Mount Hood's flanks are simply big piles of debris that have spalled off summit plugs and domes. That smooth slope, flattening distally, has very little holding it in place other than gravity. When there are heavy precipitation events, and water starts pushing the rubble around, enormous amounts can mobilize all at once. I hope I'm not alone in saying this sight fills me with awe, and increased my respect for volcanoes, even those that tend not to erupt explosively- such as Mount Hood.

Incidentally, the small "boxy" object on the horizon near the center of the photo is the upper ski lodge at the Timberline Ski Area.

Photo unmodified. October 10, 2012. FlashEarth Location.

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