Photo of Oso slide

Discussion in 'Fly Fishing Forum' started by Richard Olmstead, Apr 3, 2014.

  1. Richard Olmstead

    Richard Olmstead BigDog

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    Kim,
    Looking at the sat images of the area, I think you are mistaken that the area above the slide is not conifers. The area below the old slide scarp face (which includes a substantial portion of the slide area north of the river) appears to be deciduous. This is the area impacted by the 2006 slide and was probably mostly alder and bigleaf maple, but the area above the scarp, and, thus, the zone where most of the water is entering the soils, is second growth conifer forest, probably mostly Doug fir and western hemlock.

    Dick
     
  2. Kim McDonald

    Kim McDonald member

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    Richard, you're a right in your analysis, far better than the video...if you look at the "cut" that was caused by the slide, my sense is much of that soil had low infiltration rates (mineralized soils are good for Doug fir and so many of the lowland hills which are perfect Doug fir timberland are similar soils). In addition to the till layers, I would also suggest the upper layers were so saturated, causing enormous pressure on an already destabilized cut-bank at the toe slope, an inverse pyramid if you will.

    On a policy level, these cuts occurred during the last "gold rush" in housing. Just before peak. And there is very little cutting on public lands here in Washington, so the pressure on what remains of privately held timber land to produce product is enormous. And obviously the timber company wanted to get out as much as they could...in reality that last cut was a fairly small cut...

    I haven't looked at the ownership of the cut areas, were they also owned by Summit and Grandy Lake? Or was someone selling the timber to pay for a kid to go to college?

    Kim
     
  3. Kim McDonald

    Kim McDonald member

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    No, you're right. I was indicating the area just above the slide and what did slide. That was hardwood.

    Kim
     
  4. Richard Olmstead

    Richard Olmstead BigDog

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    I read in one of the many articles about this slide (perhaps the one Kent cited) that the timberland above the slide was owned by a lumber company and that they protested the recommendations to prohibit further cutting, citing that the value of the timber in that area was worth 3/4 to 1 million dollars. Unfortunately, in small county politics, that kind of money talk pretty loudly.

    D
     
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  5. Kim McDonald

    Kim McDonald member

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    Actually it's DNR who they protested to, Snoho county has nothing to do with timber permits. Did they own the timber rights or the underlying land, also? I can look on the assessor's records, I just wonder if someone knows.

    Kim
     
  6. Kent Lufkin

    Kent Lufkin Remember when you could remember everything?

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    I saw that story too Dick. I believe it mentioned how the timber company argued forcefully and loudly against any proposed restrictions on cutting. Having grown up in a small town where almost every job was directly or indirectly dependent on the timber industry, you're exactly right about hows the locals oppose anything that might jeopardize the cash flow they rely on.

    K
     
  7. Kim McDonald

    Kim McDonald member

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  8. Patrick Allen

    Patrick Allen Active Member

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    Had a biologist tell me once an adult Doug fir can hold up to 400 gallons of water just in its limbs, don't know how much the trunk and roots could hold. Nobody can say clear cutting has any positive effects on a stream but I still understand that it is or was in the past a necessary evil to developing society
     
  9. Jim B

    Jim B Active Member

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  10. smc

    smc Active Member

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    Richard, your statement causes me to wonder: Do you know the logging history of the Stillaguamish valley? Clearcutting has been going on there at least since the railroad reached Darrington in 1901. Do you know when those old "pre-clearcut" slides (as you refer to them) occured? Do you know when that area was originally logged of it's old growth timber, not 2nd or 3rd growth?

    Those historical slides just to the west of the current slide, as revealed by lidar, are impressive, for a number of reasons.

    Steve
     
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  11. Kent Lufkin

    Kent Lufkin Remember when you could remember everything?

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    While clearcutting may well have played *some* role in the most recent slide, it was probably not the only factor. An earlier Seattle Times article on lidar showed a number of earlier slides including one several times larger that the last one. Many of these slides date back centuries so it's obvious they predated any logging activity.

    The cause of the most recent slide may well have been due to a combination of factors such as loosely-packed glacial till soil, heavy rain that caused saturation, a steep slope undercut by a meandering river channel, as well as the removal of trees which would have helped absorb excess groundwater.

    K
     
  12. Salmo_g

    Salmo_g Active Member

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    SMC,

    I think the low elevation old growth in the valley was pretty well logged out in the 1930s, certainly before WWII. After the war, logging evolved to larger trucks and more power equipment and significantly, higher elevations. Old growth was pretty well finished in private land at all elevations by 1970, and was still being logged on public land, mainly USFS, all the way through the 1980s, but usually at higher elevations.

    It's the logging that has occurred in higher elevations that involves steeper and longer slopes, logically. And that is how logging has contributed to so much mass wasting and sediment erosion that caused so much more stream degradation than logging in the early 20th century.

    The north cascades is characterized by steep unstable slopes that become extremely unstable when disturbed. Hence the linkage to logging, since that is the main disturbance, but other road building has also contributed its share. These mountains have been sliding since the recession of the last glacial ice age. Logging disturbance just accelerates the process and becomes a contributing factor in many, or most, slides.

    Sg
     
  13. Keith Hixson

    Keith Hixson Active Member

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    The South end of the Yakima Canyon there is a large slide, just before Roza. Also across from the Boat Launch on Pend Oreille Lake at Farragot State Park there is massive landslide. I'm sure these all happened without any of man's interference. I think they are more common than we realize.
     
  14. Davy

    Davy Active Member

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    thanks Reardon
     
  15. smc

    smc Active Member

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    I agree that slides can and do happen independent of logging activity and that the causes can often be complicated. I used to log, my grandfather was an old time logger. Shoot, I live in a log house. Sometimes I even hug my logs.

    Was just curious as to how Richard, whose opinion I respect, came to his conclusion that the earlier slides were pre clear cut logging in that area.