Guest post by Donald R. Prothero
This post on the Oso landslide originally appeared on skepticblog. We have republished it with the author’s permission.
Civilization exists by geologic consent, subject to change without notice.
—Will Durant
For my post this week, I originally planned to write about the 50th anniversary of the Great Alaska earthquake, March 27, 1964. It was the largest measured quake in U.S. history, measuring 9.2 on the moment magnitude scale, and caused huge amounts of destruction in southern Alaska. It also profoundly changed the science of geology as well, since it proved that subduction zones were real, and showed us how the land changed after subduction zone earthquakes. And then as I finished this post on March 28, the earthquakes along the Puente Hills fault started to roll in. It seemed that earthquakes were the theme of the week!
But then another disaster grabbed the headlines, and pointed to some important issues that seemed even more timely. On Monday, March 24, we heard the news of the gigantic landslide that buried the tiny town of Oso, Washington, about an hour north and east of Seattle. When I originally wrote this (March 28), the official death toll was 25, but over 90 were missing and feared dead. At last count it is 28 dead, 22 still missing. Most of the news coverage of the story focuses on the horrors of thousands of tons of mud and rocks roaring down on people in a matter of seconds, burying them alive or crushing them under the enormous weight of wet mud, ripping houses and cars to shreds, and even shredding the clothes off the bodies of the victims. In the weeks before the slide, over twice the amount of the normal rainfall fell, saturating the ground and increasing the pore pressure so the sediment was like quicksand or wet concrete. The slide material itself was made of ancient glacial lake and valley sediments, mostly porous sand that can absorb a lot of moisture, and is loose and crumbly, so when it is saturated, it will flow. Witnesses described the debris flow as a “fast-moving wall of mud” containing trees and other debris cutting through homes directly beneath the hill. A firefighter stated, “When the slide hit the river, it was like a tsunami”. In numerical terms, the size of the mudflow is staggering. It’s estimated at 15 million cubic yards moved all at once. A Washington state geologist said the slide was one of the largest landslides he’d seen. The mud, soil and rock debris left from the mudslide is 1,500 ft (460 m) long, 4,400 ft (1,300 m) wide and deposited debris 30 to 40 ft (9.1 to 12.2 m) deep.
But many of the news reports talk about the slide as if it were completely unexpected. This is definitely not true. In fact, it has been studied by geologists for decades, and was known to be a very active and dangerous slide area, with great potential for a catastrophic failure that would overrun the town. The locals knew of the problem, and called it “Slide Hill”; geologists had also given the earlier slide events names, such as the “Steelhead slide”. Some of the more recent history of the slide events include:
- 1949: A large landslide (1000 feet long and 2600 feet wide) affected the river bank
- 1951: Another large failure of the slope; the river was partially blocked
- 1967: Seattle Times published an article that referred to this site as “Slide Hill”
- 1997 report, by Daniel Miller, for the Washington Department of Ecology and the Tualialip Tribes
- 1999: US Army Corps of Engineers report by Daniel and Lynne Rodgers Miller that warned of “the potential for a large catastrophic failure”; logging the hillsides was increasing the risk
- 25 January 2006: large movement of the Steelhead landslide blocked the river
- 2010 FEMA report considered the slide area a serious risk for catastrophic failure, with the potential for much loss of life and property
As geologist Daniel Miller (who mapped and analyzed it in 1997, and also in 2006) discusses, there were many warnings from geologists that this slide was very dangerous, and had a great potential to jump across the river and crush the town on the other side. Many mitigation efforts were tried, but all were futile. The slide was too large and too fast-moving for any puny human efforts to stop it or slow it down. The slide was continually destabilized by the river eroding away the toe of the slide on the river bank, which then allowed more slide material to shift downhill as the material holding it back had vanished.
Map showing the area of the slide and the houses buried in the Steelhead Drive neighborhood
The year 2006 is particularly crucial. Right after the huge slide event of Jan. 25, 2006, Daniel Miller revisited the area. He saw that instead of people moving out, five more new homes in the Steelhead Drive neighborhood were being built. Even as they could still hear the huge tree trunks in the recent slide snapping in two, more nails were being pounded in. Ironically, a new 2006 law in the State of Washington had gone into effect prohibiting the building of more homes in danger areas such as this. As Miller put it:
That’s why he could not believe what he saw in 2006, when he returned to the hill within weeks of a landslide that crashed into and plugged the North Fork of the Stillaguamish River, creating a new channel that threatened homes on a street called Steelhead Drive. Instead of seeing homes being vacated, he saw carpenters building new ones. “Frankly, I was shocked that the county permitted any building across from the river,” he said, “We’ve known that it’s been failing,” he said of the hill. “It’s not unknown that this hazard exists.”
Later that summer of 2006, the state installed a “crib wall” (a huge fence made of long posts and boards) to hold the slide back and promote fishing in the river. This structure was no match for the actual slide that came down last week, only 8 years after it was built. Yet long after the 2006 zoning law changes, and the warnings of geologists after the 2006 slide event, the building was allowed to continue in this hazardous area. Logging on the hillside above the unstable land persisted, even though experts warned that it would destabilize the slope once the trees died and the roots vanished. The 2010 FEMA report was the most recent to warn of the extreme hazards of the area, and it was widely reported in the local newspapers and a big topic of discussion in town—yet no one heeded the warning and moved out.
As Miller wrote last week when he pointed out that the landslide had been predicted by many people,
[I attended] “a community meeting to discuss my analyses—after a landslide in 2006 felled trees and crashed into the North Fork of the Stillaguamish River across the valley into the edge of Steelhead Haven. One response to my presentation, I was told, was that I was there to take their land. Construction of new homes continued, even after 2006. In some cases, people were informed of the risk, but didn’t trust the messenger, or decided it was an acceptable risk. I learned that some people were unaware that they lived across the river from an active landslide.”
Another aerial view of the immense slide scar and the buried houses.
In fact, the warnings of the state were not only ignored, but actually defied. For in a strange twist, the law inspired some people to fight the state’s efforts to “meddle in the private affairs of residents”. As the news of the slide came out, it turned out that one of the main activists protesting the 2006 zoning law to prevent runaway building in hazardous areas was Thomas Satterlee. He was one of the leaders of the activist anti-government “Patriot” movement, organizing armed militias in the area to fight back against the “big bad Government.” In the 1990s, he tried to declare the area as “Freedom County” and hoped to run it without any oversight from state or federal law; all of his efforts were struck down, eventually reaching the Superior Court. Satterlee was also a big advocate of the “Sovereign Citizen” movement, where individuals buy paperwork from con-artists who claim that by filling out and filing the paperwork, they can become “sovereign citizens” independent of the jurisdiction of state and federal laws, and no longer required to pay taxes or obey any laws they object to. (Legally, this is false, and every time they have gone to court, they lose). Advising various tax protestors, Satterlee (who never went to law school) practiced law without a license (for which he was found guilty in 2002), and he and his group even threatened the local sheriff if he tried to stop them.
In the case of Oso, Washington, Satterlee was particularly active in fighting the 2006 zoning law, whose primary intent was to prevent excessive building in the region, especially in hazardous zones below the landslide. His acts of defiance influenced his neighbors, who also ignored the law and the warnings of expert geologists. Instead, they chose to live in a clearly identifiable area of great hazard. Some of the victims of the slide, who knew about the risks and openly ignored expert advice, are no “innocents” who had no warning. Those who never heard of the risk, however, bear no blame for staying in a danger zone. In another ironic twist, Satterlee apparently paid the ultimate price for his defiance of experts: he and his family are among the missing and presumed dead.
But this raises a larger issue of risk management. Should the government have the right to protect people from their own stupidity, and force them out of harm’s reach since they refuse to listen to evidence? In the case of some kinds of clearly identifiable immediate danger, there is no question that it should. For example, during the 1980 eruption of Mt. St. Helens the Federal government created a “red zone” around the volcano, and nearly everyone was evacuated. Only a few who scoffed at the law (such as Harry Truman of Spirit Lake Lodge, who refused to move, and entertained reporters with his defiance of the experts) stayed in the “red zone”—and they all paid with their lives (along with geologist David Johnston, who was doing his job monitoring the volcano, but died because he turned out to be too close when the mountain blew out sideways rather than vertically). Other volcanic eruptions in other countries have been handled the same way, and most people recognize that the warnings are real and they need to get out of the way.
But there are other natural hazards that are not as obvious or scary as a volcano—but just as deadly. In many places in the world, people build right in areas of frequent dangerous landslide activity, and refuse to listen to warnings—until they are killed, as happened at Oso, Washington. The same is true of houses here in southern California that are built right in the narrow mouth of canyons, filled with giant boulders brought down by huge debris flows like the Oso slide—yet they never put 2 and 2 together and wonder why they have gigantic rounded boulders in their yards. Malibu, California, is one of the most expensive communities in the state, because of its ocean views and famous community of rich people, especially from Hollywood. It also one of the most dangerous, with frequent landslides, huge fires every few years, lots of active faults and their earthquakes, and the risk of huge storm waves and even tsunamis. On the coast between Ventura and Santa Barbara is the tiny surfer’s town of La Conchita, which has been hit by two giant catastrophic slides, one in 1995, the other in 2005, killing 10 people, and burying half the town—but the rest of the residents have not left, even though it’s clear that they are in great danger.
To the north of our San Gabriel Mountains are towns like Palmdale, Wrightwood, and Frazier Park, which are all built directly on the valley of the San Andreas fault. Even though this fault is well known, it’s been locked and building up tension since the last quake in 1857, and it’s considered overdue to move and cause “the Big One”, people refuse to move out of the danger zone. And of course, many states have huge areas where people have built on active floodplains, and every few years, they are washed out of their homes and farms, often at great loss of life and property. No matter how often geologists remind them that “floodplains are for floods,” they persist in returning to these fertile but very dangerous areas, only to experience another very predictable disaster every decade or so.
So where do we draw a line between the state protecting people from their own stupidity, and the rights of individuals to do as they please? In a volcanic eruption, most people agree that the state should get people out of harm’s way. But for most other hazards, the state has little power to protect people from their own foolishness. It’s not just a simple matter of letting individuals do as they please, even if they risk their lives unnecessarily and voluntarily ignore experts and stand in front of a loaded cannon with the fuse burning. These people may pay a price for their foolishness, so do but their loved ones who are too young or uninformed to make their own conscious decisions. Nor is it purely a matter of individual rights. It affects all of us. When a very predictable disaster, like another large flood in the Mississippi-Missouri river system happens, we all pay the price in the taxpayer dollars that are spent saving people from their own foolish decisions. Those of us who buy insurance pay higher rates because fools take unnecessary risks, and make it more costly to insure those of us who don’t deliberately endanger ourselves. When does society have the right to prevent people from killing themselves, because they are a burden on all of us in higher taxes and insurance rates? As always, the rights of individuals are not absolute, because we all have to share a common society and behave in a fashion that does not put others at risk, or cause a burden to be placed on other taxpayers or insurance holders who don’t indulge in risky behavior.
As Jon Schwartz wrote in the New York Times, most of the time the state has great difficulty in regulating this problem because of the backlash of people who refuse to listen to geologists, refuse to use common sense, and don’t want to be told what’s unsafe:
But things are rarely simple when government power meets property rights. The government has broad authority to regulate safety in decisions about where and how to build, but it can count on trouble when it tries to restrict the right to build. “Often, it ends up in court,” said Lynn Highland, a geographer with the United States Geological Survey’s landslide program in Golden, Colo. After Hurricane Katrina in 2005, planners came up with sweeping proposals to rebuild a safer, stronger New Orleans, consolidating its smaller population into neighborhoods on higher ground, and transforming low-lying areas into parkland and drainage.“I took a lot of fire on that,” said Joseph Canizaro, who headed the Bring New Orleans Back Commission. “We were trying to save lives,” he added, but people did not want to be told where to live and what to do with their homes. Edward Blakely, who led the New Orleans recovery effort, said that when he discussed some of the proposals, “people either laughed at me or were very upset.” New Orleans is not unique, said Dr. Blakely, a professor at the United States Studies Center at the University of Sydney in Australia. “We have really overbuilt on really dangerous ground all over the country.”Builders and developers rarely want to hear bad news, said Dr. Rogers, who has served as a consultant evaluating stability risks. Soil and slopes can often be shored up, he said, but “when you tell them what it’s really going to cost to stabilize, they go ballistic on you.” He said, “I was the most fired consultant in the Western United States.” He said that little had been done to prepare the East Coast for storms like Hurricane Sandy, and that coastal residents rationalize away problems like hurricanes and rising sea levels, telling themselves “I’ll sell the place before that” or “The scientists don’t know what they’re talking about” or “My neighbor will get hit, but not me.” A prominent libertarian legal thinker, Richard A. Epstein of the University of Chicago Law School, said that the case of Oso should be simple, however, because of its history of landslides. “The case is a no-brainer in favor of extensive government regulation in order to protect against imminent perils to life and health,” he said. “I’m a property guy, but I’m not a madman.”
There have been success stories. After the town of Valmeyer, Illinois, was obliterated by one of the many recent Mississippi River floods, the survivors chose to rebuild the town on the bluff above the floodplain. Yet as Jon Schwartz points out:
The attraction of risky places can be strong; they can be as beautiful as they are deadly. Nicholas Pinter, a professor of geology at Southern Illinois University, said that he took his students to see the site of the former town of Valmeyer. As they drove along the rich flood plain, he recalled, “all my students could think of was that this would be a really good place to live.”
As in any decision like this, the answers are not always clear cut. Geologists have identified hundreds of geologic hazards, and often give very precise estimates of risk or the likelihood of a disaster happening. Yet as scientists, we geologists get very frustrated when people scoff at the scientific evidence, and then endanger themselves and others despite every possible warning. This is the bigger lesson of the Oso disaster.
Donald R. Prothero is a professor of geology at Occidental College and coeditor or author of many books, including Catastrophes! Earthquakes, Tsunamis, Tornadoes, and Other Earth-Shattering Disasters, Horns, Tusks, and Flippers: The Evolution of Hoofed Mammals, and The Evolution of Artiodactyls, all published by Johns Hopkins.
