
Watching a Ridge Slide in Slow Motion, a Town Braces for Disaster - curtis
https://www.nytimes.com/2018/01/21/us/washington-rattlesnake-ridge-landslide.html
======
jonknee
This article has a LIDAR (I believe) image showing the movement... Scary
stuff, especially when you see the date stamps between images. It's like
watching geology on fast forward:

[https://www.seattletimes.com/seattle-
news/science/dramatic-n...](https://www.seattletimes.com/seattle-
news/science/dramatic-new-images-show-rattlesnake-ridge-slide-moving-over-
time/)

~~~
ambrop7
If anyone else is confused: the dates there are MM.DD.YYYY not DD.MM.YYYY

~~~
letlambda
Friends don't let friends use ambiguous date formats.
[https://xkcd.com/1179/](https://xkcd.com/1179/)

------
poulsbohemian
Drove through there last week. The state has 40ft containers at the bottom of
the hill as barricades, plus there is a low spot below the area that is
cracking. That stated, there isn’t _that_ much room there for all the dirt
that is likely to come down and even to a lay person it looks very reasonable
to assume the highway will be unavailable for some time after it finally gives
way.

~~~
unspecified
Just to be clear, those containers are only a barricade against falling rocks
while the road is still open. If the ridge does let go, those barricades are
going to do exactly nothing.

[https://wsdotblog.blogspot.com/2018/01/crews-monitoring-
land...](https://wsdotblog.blogspot.com/2018/01/crews-monitoring-land-
movement-on.html)

~~~
poulsbohemian
Completely agreed. But it makes it easy to spot from the highway for the
looky-loos that way ;-)

------
gshubert17
From a video [0] of the area, it seems to me that mining activities between
the ridge and the river may be partly responsible for the slide.

[0]
[https://www.youtube.com/watch?v=7DATFoizswY&feature=youtu.be](https://www.youtube.com/watch?v=7DATFoizswY&feature=youtu.be)

~~~
jonknee
Hence the "generosity" of the mining firm:

> The company that runs the quarry has stopped operations and has voluntarily
> offered to put up evacuated residents in nearby hotels for five weeks at its
> own expense, though the cause of the crack has yet to be formally
> determined.

~~~
kevin_b_er
I wonder if they have to sign a form discharging the mining corporation of
liability before they can have the "free" hotel room.

------
adlaigordon
Why don't they dynamite it so that it collapses while everyone's extremely
prepared, instead of being semi prepared for months or longer?

~~~
SiempreViernes
From: [https://wsdotblog.blogspot.se/2018/01/crews-monitoring-
land-...](https://wsdotblog.blogspot.se/2018/01/crews-monitoring-land-
movement-on.html)

> If we start removing material or blasting it from the hillside, it will
> actually make the area more unstable, creating fissures in other areas and
> would likely release larger amounts of debris in an uncontrolled manner. For
> some perspective, we’ve spent the past several years blasting rock from the
> hillsides along I-90 as part of the project to stabilize rock slopes and add
> more lanes. When we blast, it’s in very small sections and then we excavate
> any loose material after the blast. Over the past five years we’ve removed a
> little more than one million cubic yards of material – or about 200,000
> cubic yards every construction season (April through October). The
> Rattlesnake Ridge slide is made up of about four million cubic yards of
> material.

> Also, blasting an unstable hillside simply isn’t safe. In order to do a
> controlled blast, crews need to drill into the hillside about 20 to 40 feet
> to put live charges into the hole. With the hillside moving, being able to
> drill accurately while also not causing more instability would be incredibly
> challenging. Even if the holes were drilled accurately, there’s the
> possibility that the charges won’t go off, meaning the crews would then have
> to sort through millions of cubic yards of debris looking for live
> explosives that could go off. It’s just too dangerous of a situation to put
> workers in.

~~~
trhway
>In order to do a controlled blast, crews need to drill into the hillside
about 20 to 40 feet to put live charges into the hole. With the hillside
moving, being able to drill accurately while also not causing more instability
would be incredibly challenging. Even if the holes were drilled accurately,
there’s the possibility that the charges won’t go off

with laser guidance and at $150K that would probably be more precise, safe and
efficient tool for that job here -
[https://en.wikipedia.org/wiki/GBU-28](https://en.wikipedia.org/wiki/GBU-28)

Btw, similar scale hillside slide in 2017 in Big Sur, Hwy 1
[https://www.npr.org/sections/thetwo-
way/2017/05/25/530025850...](https://www.npr.org/sections/thetwo-
way/2017/05/25/530025850/-mother-of-all-landslides-closes-section-of-
california-s-highway-1)

------
russh
Really happy I don't have to drive past that anymore.

