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Mar 26 2014

New at Rosetta Stones: Links to the Geology Behind the Oso Mudslide Disaster

I’m still researching for a post on the slide that destroyed Oso, Washington and killed so many of its residents. In the meantime, I’ve collected links from the experts, who are doing an excellent job exploring the geology behind the catastrophe. I hope a lot of future town planners and other sorts who determine where and what to build are in the audience, and click, and think.

Aerial photo of Oso debris flow. There used to be a town down there. Image shows lumpy debris blocking the river. Courtesy Gov. Jay Inslee via Flickr. (CC BY-ND 2.0)

Aerial photo of Oso debris flow. There used to be a town down there. Courtesy Gov. Jay Inslee via Flickr. (CC BY-ND 2.0)

16 comments

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  1. 1
    Lithified Detritus

    Thanks for the great links. I found the seismology connection particularly interesting.

  2. 2
    rq

    Tragic.

  3. 3
    Gregory in Seattle

    The Seattle Times had this image yesterday. It is an overlay of the landslide over a map of the town, and helps to visualize the magnitude of what happened.

  4. 4
    Gregory in Seattle

    Oh, and picky point that is starting to get on my nerves (not just you, but pretty much EVERY media outlet.) The landslide occurred about 60 miles north of Seattle, well outside the greater Seattle metro area, in an entirely different county. Calling it “the Seattle region” is like saying a tragedy in Gilroy, California occurred in “the San Francisco region”, or that something in Tucson happened in “the Phoenix region.”

    1. 4.1
      rq

      I quibble with your quibble: this is a much smaller country than the US, but a radius of about 100km of the capital (the largest city ever in this country) is counted as the ‘region of Riga’. 60 miles falls within that range, so if it’s the closest large city, it doesn’t seem all that unusual at all.
      Unless, of course, they’re playing for sympathy and scare points by using Seattle and not the actual closest large(-ish) city.

    2. 4.2
      Trebuchet

      For the national media, and for much of the country, Seattle is the only place in the state they’ve heard of. So that’s the natural reference. For you, in Seattle, or me, commonly in Everett, not so much. Note that it isn’t in Oso either, but several miles up the road.

      Nitpick for Dana: There wasn’t really a town down there, more of a neighborhood.

      The local news is announcing that they’re opening the Mountain Loop “Highway” to help people get to Darrington. That’s a narrow, windy, unpaved road that goes up into the mountains east of Everett then runs north along the Sauk River (I think) to Darrington. A very loose definition of “Highway”, and not a road I’d want to depend on.

    3. 4.3
      ryangerber

      Is it closer to Seattle than to either Portland, Vancouver, or Spokane? Yes? OK.

    4. 4.4
      rq

      But your posted image/interactive map is jsut scary….

  5. 5
    Trebuchet

    Note to Dana: The link that’s supposed to go to “Reading the Washington Landscape” goes instead to some sort of headline news site. Here’s a better one:
    http://washingtonlandscape.blogspot.com/

    It hadn’t occurred to me to use the history feature of Google Earth until a few minutes ago. You can clearly see what happened in 2006, diverting the river into what had been the north leg of Steelhead Drive.

  6. 6
    Tsu Dho Nimh

    I feel your rage … there have been enough slides at that spot in the previous century that building should have been banned.

  7. 7
    Onamission5

    I was looking through a photo slideshow of the devastation right after it happened, and in an areal view I was certain that I saw evidence of at least three other previous slides, with the accompanying debris fields, on three other hillsides.

    I am both saddened and enraged that I was not mistaken, except in that I was seeing the evidence of one massive slide, not three.

  8. 8
    Rob

    Wow, that is a tragedy. Having recently experienced a natural disaster my heart goes out to all involved.
    It also makes me very angry that authorities permitted development in an area that is so clearly littered with massive landslides and associated debris features. Although the media are describing the landslide as huge (it is on a human scale) it does not look that big on the local scale – there are certainly bigger features there. Combine that with known landslides in recent history and reports demonstrating the danger and this is truly appalling.

    If a fraction of the effort put into protecting us at airports was instead put into better zoning and planning the return on investment would be considerably better.

  9. 9
    psanity

    Ah, Dana, I knew you’d be here to lead us through this. Last night, I got a notion, and I went hunting on Google Earth to see if I could find the spot, just from the news photos. I got pretty close, but links that were posted in comments on a local news site pinpointed the spot and the history, referencing McShane. I was having trouble getting my mind around the size of it — almost a square mile. I still am.

    Considering the Hazel slide, and that these slides on dirt hills tend to just keep getting bigger until you run out of hill, I’m astonished that area was developed. Just the river would be an issue, I’d think — I mean, rivers like to straighten out those bends once in a while — but, holy moley! How could you look at the remains of that Hazel slide and think “Oh, what a lovely view” and not “That thing’s coming after us”?

    If I were writing news headlines, which no one is likely to let me do, I’d use “Geography Fights Back!” (I don’t think geology is the fighty part — it’s the science that explains how the geography is trying to kill us. Sort of forensics.)

    I’m looking forward to more explaining, Dana, as and when.

    (BTW, does anyone know how to elicit topo from Google Earth?)

  10. 10
    Rob

    Psanity @ 13,

    You can insert a path through the area you want a cross section of, save it, then right clicck on the path name and select show elevation. It is prone to odd artifacts in some circumstances so beware of odd sharply defined cliff features. they may not be real.

    Alternatively, view the area in Google maps, select map view and check the terrain option.

  11. 11
    Rob

    Opps, sorry, Psanity @ 9

  12. 12
    psanity

    Thanks, Rob!

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