Photo of Oso slide

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

  1. 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.

  2. 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
  3. 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.

    Kent Lufkin likes this.
  4. 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.

  5. 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.

  6. 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.
  7. thanks Reardon
  8. 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.

  9. I was talking, this morning, with someone from Snohomish County about the video. Apparently Dori Monson is referring to it as evidence...oh dear.
    Kent Lufkin and smc like this.
  10. One of the lidar images in the news seperates slides in the area into different age classes. The Hazel Slide is the most recent and dates back to the 40's or earlier.
    The glacial lake deposits these slides are occurring in are around 12,000-14,000 years old. Since the glaciers receded these deposits have been constantly eroding, and most of that erosion has likely been from mass wasting events like the most recent one. These deposits are on the north and south sides of the valley and may have spanned the entire valley before the river carved out a path.
    Kent Lufkin likes this.

  11. Kim,

    Is the guy who posted that video, Dori Morrison someone of note down your way? I don' know a thing about the guy. I saw that original video shortly after the slide on and that was the first time I had seen that website as well. Has Morrison identified the person on that video?
  12. Dori Monson is a radio personality. Likes to think of himself, I think, as someone who exposed government's inept moments. I had one dealing with him on some issues with infiltration based storm water management, and he totally missed the story. I personally think it's irresponsible of him to post the link to this video without, as far as I can tell, any research into the credibility of the guy who did it, his credentials, the public records requests he did on the timber permits, soil sampling he used, hydrology comprehension, etc. Just my opinion. I'm not defending the logging operations nor Washington State DNR, it's just a complicated situation which will result in a lot of litigation and I think flaming the fire by having someone of some "public stature" post these kinds of videos isn't very good.

    mat1226 and Kent Lufkin like this.
  13. SMC
    I don't know the age of the big slide to the west of the Oso slide. I infer that it is pre-clearcut, simply because it is so huge (several times larger than the Oso slide) and the southern edge of the slide forms the river channel boundary for a couple of miles. If this had happened in the 20th century, or even late 19th century, there would be some record of it.

    I tracked down the sources that I had seen previously and will link to them here. The first is a blog from a engineering geologist in Bellingham, and the second from a geologist blogging at the American Geophysical Union (a geological professional society).

    The Duke likes this.
  14. I liked the "before and after" picture posted on the on-line version of the Seattle Times. You can move the center bar to see either an aerial map or a road/plat map. Here's the link:

    Since the slide, I've been reading stories about the North Fork in old books by Enos Bradner and Steve Raymond. It's a great reminder that the area was once a paradise with cool, clear water and a wonderful run of Deer Creek Summer-runs.


  15. Roderick Haig-Brown caught his first steelhead on Deer Creek.
    Tom Bowden likes this.
  16. The "A" in that picture on the south side of the river, didn't that start to slide a few years or so ago. I can remember that it started to then stopped. They even closed the road down at that time. That whole valley is unstable. I'm surprised they let anybody build anything on them hills.
  17. A bit of historical geological perspective on the valley of the North Fork of the Stillaguamish:
    Many years ago geologists recognized the North Fork to be a poor fit for its valley. Its valley and flood plain were much wider than could be explained by the river's size. Research has shown that during the most recent glaciation the Puget lobe of the continental glacier, in its multiple advances and retreats, repeatedly formed lateral moraines which dammed the Skagit River forming large lakes and diverted its flow south into the valley now occupied by the North Fork of the Stillaguamish.

    When the Puget lobe at last retreated the Skagit was able to breach the morainal dam (located near where Concrete stands today) and resume its course to the west while the Sauk and Suiattle continued to flow north and west down the valley of today's Stillaguamish. This situation remained until a lahar (a glacial/volcanic mudflow event), originating on the slopes of Glacier Peak, dammed the Sauk near the present site of Darrington. Only when the Sauk was able to cut a new channel and begin to flow to the north and into the Skagit was the flow of the Stillaguamish reduced to something approaching its present volume.

    One can only imagine what the North Fork must have looked like with the added volume of the Skagit, Sauk and Suiattle Rivers augmenting its flow; a large river indeed. This huge river carved a wide flood plain which, to this day, allows the existing river ample scope to meander. Almost every high-water event brings minor changes to the river's course. Even in my lifetime I've seen some pretty dramatic changes: the gravel bar near Cicero where I stood to catch my first steelhead is now a six-foot-deep run, and the water from Hazel downstream bears no resemblance to its its course when I first fished there.

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