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The 2014 Oso, Washington Landslide: Completely Foreseeable

By March 25, 2014

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The large, deadly landslide that struck near the town of Oso, Washington on March 22 was a slow-motion tragedy. The first few days were the worst part of it—emergency responders were working without rest to find survivors, yet much of the ground was too dangerous to step on. The anxiety and frustration must have been terrible. So I grant slack to the weary manager of the county's emergency management department, who told the press, "The area was mitigated very heavily. It was considered very safe. This was a completely unforeseen slide. This came out of nowhere." Many people who don't know geology think that way. To geologists, what he said was mostly incorrect.

This is an area of large, well-mapped landslides. Washington geologist Dan McShane writes a blog, Reading the Washington Landscape, where he's been pulling up background information on the slide and its neighborhood. (I've had it in my Washington Geology resource list for some time.) The landscape has landslides written all over it. As McShane put it on the day of the slide, "Landslide wonks knew exactly where this slide was as soon as it made the news." Later he posted lidar maps of the area, showing the landscape with all trees and buildings removed. Take a look.

Oso slide lidar map

Outlines in red, made by McShane from county data, show some of the landslide areas. The area of last weekend's slide is the one on the right. That is to say, the latest slide was in the scar of an older one. In fact, the lower part of that older slide moved again in 2006, pushing the river southward. The area of the 2006 slide is the part that was "mitigated very heavily," meaning that the ground was drained and wreckage cleared up. Such steps can stabilize small landslide deposits, but they can't stop unstable mountainsides from collapsing over and over.

I have no doubt that the geotechnical engineers and geologists who dealt with that 2006 slide knew the overall situation perfectly well. But scientists, for better or worse, aren't in charge of things, and people determined to do what they want can't easily be made to understand the risks they're taking. Until the ideal world arrives, people need to learn on their own.

The technology that could help is easily envisioned. Sprinkle a bunch of RFID chips (or even just distinctive reflectors) on hillsides like this and map them regularly with GPS and lidar. The premonitory signs of landslides like this can be detected and warnings can be issued with good data behind them. The largest non-volcanic landslide in North American history happened just last year, inside the massive open pit of a copper mine in Utah. But because the pit was closely monitored, the workers cleared out 7 hours beforehand and not a soul was injured. The technical details were published January in the open-access journal GSA Today.

On the other hand, it would be cheaper just to keep housing away from danger zones.

About landslides and mass wasting
8 landslide types in photos
The Landslide Handbook, free from the U.S. Geological Survey
Annotated lidar image from Dan McShane


March 25, 2014 at 6:34 pm
(1) Geology Guide says:
March 28, 2014 at 10:43 am
(2) Cy Nical says:

I presume “the ideal world” mentioned is marked by perfect knowledge and perfect security. Thanks for the thought, but I’ll stay in charge of my own freedom, my own risks and my own life.

March 31, 2014 at 8:12 am
(3) as*chomp... says:

Cy…what are you ACTUALLY saying? that better knowledge, better foresight, better safety are things to NOT strive for? rather poor choice, eh? if one KNOWS that there is danger, in ranking likelihood of actuality, i am certain MOST intelligent people would be interested and act accordingly. If YOU knew for certain that a sinkhole were to develop under your house Thursday night…would you not take actions to protect your children? your spouse? your Beemer? The manner in which you express yourself indicates you think that there is NO reason to take precautions or pay attention to the dangers possible…
So, I ask again…what are you REALLY saying?

March 31, 2014 at 10:46 am
(4) Jim says:

“Cynical’s” attitude and ensuing comments by others verify what Andrew said about “…people determined to do what they want.” This is an ingrained resisted view of reality many people have driven by fear and ignorance. One news report showed there were 11 homes built in the slide area after a report by Washington state in 2000 of an extreme hazard of slides in that area.

March 31, 2014 at 10:50 am
(5) Tom Loomis says:

good article Andrew. I agree with every bit of it. It’s too bad that city and county engineers cater to the developers instead listening to geologists. It’s all about the tax base you know. Build more houses and get more tax money ignoring the hazards. Here in Rapid City, SD we had a terrible flood in 1972. It took this terrible flood that wiped out a lot of houses and killed a lot of people to enact a flood plain management program. But since then, especially recently, developers have slowly encroached upon the flood plain.

As for Cy………you shouldn’t be so critical if you have nothing to constructive to add.

March 31, 2014 at 11:13 am
(6) Carol W says:

Thank you so much for your excellent article, Mr. Alden! Right after the mudslide, I went to Google Earth to find the spot, and sure enough – the satellite photo showed the hollow from a previous landslide (or several) – and it was obvious to my untrained eye (after the fact) that this was an unstable area.
People either scream for the government to do more to protect us, or to get the heck out of our business and leave us alone, whichever works for the moment at hand. We’re fortunate to have tools – such as your articles and Google Earth – at hand with which to educate ourselves now, and it’ll be survival of those who make use of them.

March 31, 2014 at 11:53 am
(7) Andrew Alden says:

Thanks all of you for your comments, including Mr. Nical. He says things that I believe too, and everything he says is right as far as it goes. Knowledge is imperfect, governments can be remarkably stupid, and people have a right to take calculated risks for their own purposes. I want to underline one of his points in particular: there is no risk-free place, and to demand perfect safety of the universe is folly.

I agree with the rest of you that people are imperfect, governments can be remarkably stupid, and any single person’s calculated risk can impose costs on all of us.

Science offers inconvenient truths of all kinds, and it is still earning a place at the table where decisions are made. I’ve made a longer version of this argument elsewhere.

March 31, 2014 at 12:49 pm
(8) Adrian Jones says:

I am presuming that this was an esker or drumlin, or some other remains of glacial till left after the last ice age, however no where in any of the media reports or your article have I seen what the geology of this hillside actually was. Could you enlighten us please. Thanks

March 31, 2014 at 1:24 pm
(9) Andrew Alden says:

Adrian, the blog I mentioned goes into the geology. It’s glacial sediment with a big slippery clay layer inside.

March 31, 2014 at 3:29 pm
(10) David Hilyard says:

“On the other hand, it would be cheaper just to keep housing away from danger zones.”

I absolutely agree with you – but it becomes the battle between short-term private gain, and long-term public cost. Privatise the profits, socialise the losses.

March 31, 2014 at 10:09 pm
(11) Bill Dengler says:

I’m usually not one to get swept up in these comment-upon-comments, but Andrew is “right on”. It is in regards to Cy Nical that I write. In my opinion, he is one of these “…in charge of my own freedom, my own risks, and my own life”. until he’s the one who gets buried or flooded out. Then it’s, the government didn’t warn me or react fast enough to save me. Sad how many people in our society want to live by this twisted standard.

April 1, 2014 at 7:33 am
(12) P. Michael Hutchins says:

Part 1:

Possibly like Mr. Cynical, I wonder what exactly Andrew had in mind with his “ideal world”..
..in his “But scientists, for better or worse, aren’t in charge of things, and people determined to do what they want can’t easily be made to understand the risks they’re taking. Until the ideal world arrives, people need to learn on their own.”

…and his “it would be cheaper just to keep housing away from danger zones”

To me, they sound dangerously close to statism, in its sense of (self-anointed “superior” people’s) controlling people whom they have judged unable/unwilling to look after themselves.

Until the “Progressives” came along, our country remained on the moral course that our Founders set it out on: individual freedom WITH responsibility.

Now, we’ve got mostly a nanny state that believes in controlling everything under the sun by issuing regulations, rather than using the legal system based on “innocent until (unless) proven guilty”.
(Regulations punish everyone before (ie, regardless of the propriety of the) action.)

April 1, 2014 at 7:34 am
(13) P. Michael Hutchins says:

2nd part:

The Leftists of Comments 3-6 reveal how Leftists so-called “think”:
* misinterpret & bash Cy, just because he put forth an individualist view
* act as though “people determined to do what they want” is a bad thing
(Obviously, one can find/create cases wherein what given people want can imorally hurt other people – but that is not its essence. It is, however, what our current culmination-of-Progressivism, anti-American Persident preaches.)
* “Itís too bad that city and county engineers cater to the developers instead listening to geologists.”:
Right: That’s always how it is, isn’t it? Greed-driven wolves out for the almighty dollar over all else is the cause of everything that’s bad.

Consider this:

If we had a system of … ack! laissez-faire … people could build wherever they want – and/but then be responsible for the results/effects of their choices.

We’d have none of the brain-dead boondoggles such as ~federal flood “insurance”~ for pretending that flood-prone areas present no risks that shold be borne by the people who choose to live there..
..nor such as this landslide, for which WA is now applying for a declaration of a State of Emergency (ie: money to “safety net” the people who made the bad, irresponsible decisions)

FInally: Again, there are certainly instances where one person’s decision risks violating others’ rights – but that is a separate issue.

April 1, 2014 at 11:58 am
(14) Andrew Alden says:

Michael, thanks for your stern invocation of individual responsibility. I think if you went to Oso and thought about saying some of these things out loud, you’d weigh your words more carefully. Here we’re all pixels on a screen and that’s OK.

The “ideal world” I was thinking of was one where a homebuyer can easily find geoscience data AND have the education to comprehend it. In California we have a nice law that requires home sellers to inform prospective buyers when the property is near an active fault, as mapped by state-approved geologists with their data made public. I think it could be extended to other states and other situations to make the world a bit closer to ideal.

I’m not a fan of statism in the abstract or in reality. The state exerts itself in many ways, though. You favor reliance on the court system, which acts in reaction to bad things. Others here argue for reliance on regulation, which acts to prevent bad things. (Then there’s legislation, which I’m not touching thank you very much.) All I want is more respect for science, which can help cut through a lot of wrangling over case law and help evaluate complex regulations. There is progress on that score, both in the court system and in the regulatory agencies.

If you’re proposing full employment for lawyers as opposed to full employment for bureaucrats, I have to demur. I favor full employment for geoscientists to help lawyers and bureaucrats do their necessary work better.

April 1, 2014 at 9:24 pm
(15) Andrew Alden says:

Dave Petley, whose Landslide Blog is as authoritative as anything out there, weighs in on my side: “I find the decision to build new houses at the foot of the landslide to be very surprising.”

April 3, 2014 at 4:08 pm
(16) Herbert Curl says:

Andrew, Dave Petley may have found it surprising because he knows the risks, but the people building and living there did not have full disclosure. Undoubtedley many would have discounted any warning, and probably did, but at least they would have had the information.

The Seattle Times revealed today that county officials had considered offering to buy out residents after 2006 but changed their minds without telling anyone.

April 4, 2014 at 8:31 am
(17) P. Michael Hutchins says:

(part 1:)

Thank you, Andrew, for your thorough response.

I think you’re completely right about the comment-writing difference between sitting at home and soapboxing at the site itself.

If I had been in the latter context, I’d not’ve forgotten to address the issue of how the knowledge of the slide-proneness of the place might reliably get passed down (from the geologists who developed it) to people considering living there.

(so here goes:)
Since the only valid functions of government is to protect Individual Rights..
(against violation by other people – not Nature)
..we have to look to the (potential) residents themselves..
..and thus, to their individual sense of (self) responsibility.

That used to be abundant in this country, but the continuous incursions of NannyGov into our lives has just about wiped that out: Naive people now grow up thinking that every possible choice and action has been examined and OKed by the relevant czar – and everything that’s not absolutely safe has been somehow caused not to even exist.

To be perfectly clear, I should add that not even the intital survey should be brought about by government (because of the principle above). I recommend something like the old Good Housekeeping Seal of Approval here: Every responsible potential resident of a(ny) locale would check at the local residents’ GHSoA for such information.
(like flood likelihood today)

I think that addresses the first part of your ideal-world explanation; the 2nd part (education) is one of the myriad things that would be actually valued by people once nanny is gone.
(And, as with all other things, the education that’s required to understand (eg:) slide-proneness can be reduced to almost zero..
(“That hill’s gonna come down one of these days.”)
..if the layman can trust the people who are transferring the geologists’ knowledge into lay terms.)

April 4, 2014 at 8:32 am
(18) P. Michael Hutchins says:

(part 2:)

Re statism:

Yes, the state exterts itsaelf in multifarious ways – today.

I work to get rid of all state action outside of its proper functions (above).

Only via respecting the proper nature of government can one see other solutions to problems such as this.

My “reliance on the court system” is what emerges from that understanding: An action is (should be) punishable only if it can be shown to be / to have been a violation of individual rights.

Regulation attempts to erect a nanny barrier against any possibility of actionable behavior.

And – apart from the immorality of that – we all have seen how not-great government is at doing virtually anything.
(outside of its proper sphere; w/in that sphere, it does enormously better:
(& that’s no coincidence)
Think about our police, courts, and national defense in this light.)

I don’t understand your distinction between regulation and legislation, since in my understanding, regulation must be legislated.

(good) Science deserves unlimited respect.

Unfortunately, our problems today don’t stem from failings of science; they do rather from failings of philosophy.

Science and technology have so outstripped our understanding of how to build functional human institutions that we’re bound to destroy ourselves unless that gap is closed.

Finally, it is true that my approach would resuult in more lawyers(‘ work). But they would be people working to protect individual rights, rather than shysters chasing ambulances.

Re “full employment for bureaucrats”, there would be virtually no bureaucrats in a proper government.

And re geoscientists: valid, objective science should underly all of human action.

April 6, 2014 at 9:30 pm
(19) Jeff says:

The area that failed is an old lahar, even though the latest 7.5 minute Oso quad does not show it. I spoke with the DNR geo folks 2 days before the event and was told by them that this was a lahar deposit.

April 7, 2014 at 12:52 pm
(20) Andrew Alden says:

Thanks, Jeff. That’s the trouble with geologic maps—they’re always a simplification.

April 10, 2014 at 11:17 am
(21) E. Martinez says:

Look at the geologic data and you can all see for yourself where the landslide deposits were and are.
LIDAR and digital elevation models are certainly valuable, but what about old fashioned elevation contours, an old fashioned geologic map and an old fashioned aerial photograph?

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