Road to Darrington Washed out in Mud Slide, 3 Dead

[OlympicMtnBoy]

Just got home and saw this, I know a lot of us have driven that road (Hwy 530) to Darrington many times. Condolances to the family members and best wishes for the still missing:

 

http://seattletimes.com/html/localnews/2023201818_mudslidexml.html http://seattletimes.com/html/localnews/2023201818_mudslidexml.html

 

3 die in mudslide east of Arlington, 6 homes destroyed

Mud slammed Saturday into homes near the Snohomish County town of Oso and cascaded over state Highway 530, into the Stillaguamish River, which is backed up by debris.

 

 

[mountainsloth]

Shit! Hope Hanman and family are ok.

[genepires]

same thoughts. saw a satellite photo on the news of the area and it looks like the slide was to the north and far east or west of his house. Could not see the side road that his house is on which is to the south of the hwy.

 

hope that he will chime in soon.

 

 

[num1mc]

Shit! Hope Hanman and family are ok.

 

Ditto.

 

I bet Chief Dennis Fenstermaker of Darrington FD is busy too. Denny is a old time climber with a number of FA's, including the Zipper at Index. He is also a SFD firefighter and head of the High Angle rescue for SFD.

[mattp]

I talked to Hanman yesterday and they evacuated but are fine.

[hanman]

Hi all- We saw many choppers in the air all of the sudden, didn't realize what had happened. Power, phone and internet all went out. I looked out at the Stilly which is only about 300 feet away from our home, and the river had dropped to the lowest condition I have ever seen in an hour long period. I figured something like this happened, so we got out with the fam and pets in about 5 minutes. It just seemed really surreal. I'm really sorry for all the affected community, there are only 320 or so residents in Oso proper, so everyone has a stake or close friend impacted.The toll on the responders was quite evident as we drove through to get a few things from the house yesterday. They have performed quite a difficult and painful task and continue to do so at considerable risk.

 

Thanks all for the good wishes-

 

Mark Hanna

[G-spotter]

NPR and BBC just reported than in addition to 8 confirmed dead, as many as 108 people are missing.

[tvashtarkatena]

18, not 108

[JasonG]

Dru is right on this one, they just updated it. However,I expect it to be revised downwards significantly once a few more days go by. Still, many folks we've worked with over the years on Steelhead Drive are no longer with us....the scale of this most recent slide is hard to comprehend. So much bigger than 2006.

 

I've worked as a fish bio on the Stilly for the past 14 years and this is as bad of an event as I'm likely to see in my career.

[JL1216]

http://blogs.seattletimes.com/today/2014/03/update-on-search-of-mudslide-expected-at-9-a-m-today/

 

Seattle times says 108. Hope they are wrong.

[ivan]

goddamn gravity

[wayne]

Much sorrow for the catastrophe, and the people involved.

Was that hill one giant moraine? Seems like it could happen anywhere near a hill. Yikes

[olyclimber]

you can see a couple photos of the slide in the WSDOT flicker set:

 

Edited March 24, 2014 by olyclimber

[G-spotter]

Was that hill one giant moraine? Seems like it could happen anywhere near a hill. Yikes

 

It's thick, uncompacted glaciolacustrine sediments with a thin cap of glaciofluvial sand, overlying thick compacted till.

[tvashtarkatena]

Damn. I heard 18 on NPR this morning and was hoping that was a typo. 18 is not a small number in and of itself. Grim.

[JasonG]

The LiDAR for the Hazel reach is sobering. In the last several thousand years there have been several slides larger than the one that we just witnessed. Dru nailed the geology, something that plagues the NF in several reaches. Think of it as a combination of of moraine and lake sediments from when the Puget Lobe blocked the NF valley mouth.

 

The thing that is interesting to me is that, contrary to what the ST reported, the river was not actively cutting at the toe of the slide. We built a several thousand foot log revetment to keep the river away from the toe of the slide after the 2006 event. It was performing as designed and the material behind the crib wall (extending up to the old head scarp) was very low angle and not in danger of failing. This slide originated much higher (a couple hundred feet above the old head scarp) and overran the old debris, going very much farther than I had expected. Amazing.

[G-spotter]

It looks like it started as a big rotation: you can see the trees all fallen over on the intact top block. Then when that hit the lower sediments they fluidized and boom.

[catbirdseat]

Has anyone seen the slide on Jumbo Mountain from about ten years ago? It was big and cut the road up Squire Creek. I wonder in what ways this is similar or different to that one.

[num1mc]

Jumbo Mountain was probably a failure in the melange bedrock, which the scoured wet debris and the glacial veneer as it flowed downhill. It could have also originated as a relatively small slump in a sedimentary veneer up high.

 

Hazel/Oso is a huge classic slump

Edited March 27, 2014 by num1mc

[JasonG]

As Mr. mc said, they are very different. To my eye the Jumbo slide started with a chunk of cliff peeling off and impacting the slope below, causing a shallow rapid slide of mostly coarse material. The Steelhead Haven slide of 2014 is a classic deep seated rotational failure as described above.

[Good2Go]

How about the Naches slide? Seems pretty analogous, at least with respect to the quarry and river at the bottom.

[JasonG]

Similar rotational motion, but very different geology: http://seattletimes.com/html/localnews/2011077973_landslide15m.html

[olyclimber]

Jason, when you say "rotational", what is actually rotating? It is just the whole mass of the slide?

[olyclimber]

Yeah...I know...LMGTFY

 

 

[max]

How about the Naches slide? Seems pretty analogous, at least with respect to the quarry and river at the bottom.

 

Or the Hwy 97A slide...?