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Apr 18 2013

New at Rosetta Stones: Wherein We Return to Mount St. Helens At Last

Stupid trees. They’ve been giving me fits. It all seemed very simple: volcano go boom, trees fall down, end of story. But we all know it’s more complicated than that. And, of course, this is the first time I’ve written a Mount St. Helens post with Dragon. But I eventually wrestled data into some semblance of order, extracted a story about the bizarre directions bits of a lateral blast can move in, and Dragon did an admirable job figuring out what I was talking about. Smiles all round.

So, anyone want to hazard a guess as to which direction the blast was coming from in this photo? It’s hard, I know, but you can do it!

 Stump of fir tree 8 km north of Mount St. Helens showing splinters tilted away from volcano and abrasion on side toward volcano. Photo by R.B. Waitt, Jr. Skamania County, Washington. 1980. Figure 265, U.S. Geological Survey Professional paper 1250. Image and caption courtesy USGS.

Stump of fir tree 8 km north of Mount St. Helens showing splinters tilted away from volcano and abrasion on side toward volcano. Photo by R.B. Waitt, Jr. Skamania County, Washington. 1980. Figure 265, U.S. Geological Survey Professional paper 1250. Image and caption courtesy USGS.

You should’ve done brilliantly, especially if you, y’know, read the post. Stay tuned for the next time we return to Mount St. Helens, because that’s probably when I’m going to please the pyromaniacs in the audience. Heh.

 Aerial view looking west, showing massive tree blowdown surrounding Obscurity Lake, northeast of Mount Margaret, after the eruptions of Mount St. Helens. Photo by R.P. Hoblitt. Skamania County, Washington. July 6, 1980. Pages 688-689, U.S. Geological Survey Professional paper 1250. Image and caption courtesy USGS.

Aerial view looking west, showing massive tree blowdown surrounding Obscurity Lake, northeast of Mount Margaret, after the eruptions of Mount St. Helens. Photo by R.P. Hoblitt. Skamania County, Washington. July 6, 1980. Pages 688-689, U.S. Geological Survey Professional paper 1250. Image and caption courtesy USGS.

9 comments

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  1. 1
    rq

    That second photo, that is just… wow. Mindblowing. All those trees falling. Nearly at once. Like the ‘we all fall down’ part of Ring around a-rosie.

    1. 1.1
      rq

      PS Awesome post, as always. You have a way of explaining all the details in an exciting yet clear manner – you know, it’s pretty dry information, but the way you present it, it’s almost nerve-wracking. :) Thanks again for another birthday-like post! :)

  2. 2
    azportsider

    Agree with rq, except for the part about it being dry information. I think it’s pretty exciting stuff, the more because of your way with words.

  3. 3
    Trebuchet

    Wonderful as always! We’ll have to schedule another visit sometime this summer!

  4. 4
    jmonserud

    I really like how you’ve taken segments of the Mount St. Helens blast, broken them down and made them all extraordinary. Excellent research, writing and reading!
    I do have some stuff I’d like to show you…I’ll email you.

  5. 5
    Onamission5

    Amazing. Those splintered stumps, it occurs to me, look very much like the moisture inside them had been superheated and expanded the wood while their trunks were being twisted and blown down. They splintered much in the same way that I remember this old growth fir splintering when it was hit by lightning in front of my house as a kid. Difference being the St. Helen’s trees are prone while that tree– or what was left of it, I should say– remained upright.

    1. 5.1
      rq

      Perhaps due to the heat being applied more or less vertically rather than horizontally (as in the St Helen’s situation)?

      1. Onamission5

        Indubitably. ;) I was thinking, looking at the picts, that the trees look much like they’d not only been blown down by force of pressure but also super-heated internally, and was wondering out loud if that could have been a factor in the way they splintered. Blown down and also burst apart from the inside vs. merely (merely, hah) shredded by external force.

        1. rq

          I wouldn’t be surprised if that was the case at all, with such heat going through the tree. Especially if the heat moves through the tree, super-heating it directionally (as it were), it would shred starting from the super-heated, steaming sections, and would break easier in the direction in which the blast was moving (away from where the heat is coming). This would make a lot of sense, and also, as you say, contribute to the shredded appearance. It does seem to imply a finely tuned (by which I mean not like a wall but lots of little points) force, to split the tree like so. Brute force usually knocks them down and breaks them, but in larger chunks; either the force was extra-brute to shred them (which seems weird, to use a bigger wall for a finer cut), or the heat was doing its thing on the inside (and, getting down to the cellular level, could cut very fine, indeed).
          If you see what I mean.
          I’m pretty sure I’m agreeing with you here, just thinking aloud for fun!

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