On Saturday, March 22, 2014, at about 10:37 a.m., a catastrophic landslide hits Steelhead Haven, near the community of Oso, between Arlington and Darrington in Snohomish County, with a loss of 43 lives and with several survivors sustaining significant injuries. It is to date the deadliest landslide disaster in United States history. The landslide occurs in the 29400 block of State Route 530, about 17 miles east of Arlington, and destroys more than 30 homes in the small community of Steelhead Haven. It creates a debris field a square mile wide and 20 to 80 feet deep. The slide blocks the North Fork Stillaguamish River and covers an approximately 2,000-foot-long stretch of State Route 530, which will result in its closure for more than two months. After-effects of the disaster include severe impacts on the local economy, on transportation, and on the environment. State officials will estimate capital losses associated with it to be at least $50 million. Snohomish County manages development in the valley. The Washington Department of Natural Resources regulates logging in the area. The Stillaguamish Tribe of Indians has fishing rights in the North Fork Stillaguamish River.
"The Houses Are Gone!"
The first moments of shock at the massive landslide were recorded in the first calls to 911, which are public records under state law. Among the calls for help, emergency dispatchers heard:
"'There are people here screaming for help!'
"'I can't believe this. Oh my God. We need everybody,'
"'It's collapsed on several of them and they're trapped,'
"'There's power lines down ... Holy Crap'" ("Shock, Horror in 911 Calls").
Amy Miles, a Darrington High School athlete, was at the home of her boyfriend Quinten's parents, Michael and Laurianne Lincoln. She'd packed a lunch for Quinten and he'd driven off to work and she was on the porch about to walk the dog. "She heard a tremendous rumbling and snapping," according to an article in The Seattle Times. "She looked up and saw Douglas firs falling and breaking and splashes of water shooting up through the woods. Mud and tree limbs raced up the long driveway toward the porch in waves." She thought it was the end of the world. She ran in and pounded on the bedroom door of Quinten's parents, screaming, "There's a flash flood! Or Something!" ("Mudslide Survivors ...").
Mike Lincoln got up and bolted out the door. The noise, he said, "was awful. It was the sound of ten thousand things hitting each other" ("Mudslide Survivors ..."). The houses of two neighbors were lying in pieces on the road. From the McPhersons' house came the sound of tapping. Mike Lincoln was the 10th caller to 911. He and Amy Miles ran to find an axe and, along with first responders, helped in the rescue of Gary "Mac" McPherson. McPherson's wife, Linda McPherson, who had served for years as the Darrington town librarian and who was a member of the Darrington school board, did not survive.
Police and firefighters began rescuing around the edges of a "massive and treacherous" debris field ("Mudslide Survivors ..."). The devastated area extended for approximately one square mile. Rescuers dealt with a soft and "quicksand-like" condition of the saturated debris (GEER Report, 86). Snohomish County put two helicopters in the air. The United States Navy based in Everett sent a third. One helicopter, Snohawk 10, was able to rescue 4-year-old Jacob Spillers. Volunteer helicopter-rescue technician Randy Fay "spotted two men fighting through the mushy silt, trying to save a child" ("Mudslide Survivors ..."). One of the men reached the little boy, but both became completely mired in the mud. The helicopter hovered, Fay climbed down and threw a line, and the man tied it to Jacob.
As the child was being hoisted, his pants fell off and he was cold and shivering. The helicopter crew had the heater on full blast, and lowered him to the roadside to the care of Robin Youngblood, whom they had just rescued. Youngblood recalled, "I stripped him down, wrapped him in blankets, told him I was a grandmother and I would hug him until help arrived" ("Mudslide Survivors ..."). Jacob's mother, Jonielle Spillers, was at work when the landslide occurred. She found Jacob by calling around to all the hospitals. At the time of Jacob's rescue, her husband, Billy L. Spillers, and their three other children were missing. They did not survive the landslide.
Amanda Skorjanc was that morning holding her five-month-old infant and looking out the window when, "Houses were exploding, and the next thing I remember -- well, the next thing I see -- is our neighbor's chimney coming into our front door." She turned and held on to her infant, Duke. "I held onto that baby like that was the only purpose I had" ("Amid 'Exploding' Houses ..."). Mud and debris carried mother and child 600 feet. Loggers rescued them and they were airlifted to Harborview Medical Center in Seattle.
State of Emergency
Washington Governor Jay Inslee (b. 1951) declared a state of emergency and called the destruction "unrelenting and awesome" ("Danger Lingers ..."). The search and rescue, and later, recovery (of bodies) operation was massive. Searchers included Snohomish County firefighters, Washington State Patrol personnel, Washington Fish and Wildlife police, tribal police and other personnel, 70 people from the state National Guard, a team from the Federal Emergency Management Agency (FEMA), and relatives and residents, including many experienced loggers. Ground-penetrating radar and cadaver dogs assisted searchers, who waded through deep mud, sawed through massive logs, and sifted debris by hand and with heavy equipment.
Master Sgt. Chris Martin of the Washington State National Guard, speaking from Oso on PBS NewsHour, described the debris field: "It's kind of like they took a blender to the landscape ..." (PBS NewsHour, March 27, 2014). Jared Grimmer, a high school teacher in Idaho Falls who returned with his brother to his hometown, Darrington, to help with the effort, described a debris field that "looks like the moon punctuated by clay blocks the size of semis" ("Grit and Heart ...").
Food and shelter aid poured into Oso and Darrington. At the Darrington Community Center, volunteers served hot meals to survivors, searchers, and relief workers. Chaplains were on hand to offer counseling. As operations continued, United Way of Snohomish County, Cascade Valley Hospital Foundation, and the American Red Cross raised several million dollars to aid survivors and their communities. Funds came from many individuals, organizations, and tribes.
Darrington mayor Dan Rankin, a former logger, presided over nightly town meetings, and "pledged assistance, shed tears, hugged the bereaved, and opened the microphone to anyone with a grievance" ("Small-Town Washington State Mayor ..."). At one Friday-night meeting attended by both of Washington's United States senators, two U.S. representatives, and the state's secretary of transportation, Rankin received the largest ovation. "I want my town to be whole and well and I want them to stop hurting and I want them to have the things that we need," he said ("Small-Town Washington State Mayor ...").
On April 28, 2014, Snohomish County Sheriff Ty Trenary announced the decision to end the "active search" for victims ("Hunt Cut Back ..."). On that date, two bodies remained missing, that of 53-year-old Steve Hadaway, who had been installing a satellite TV dish at a home, and that of 44-year-old Steelhead Haven resident Kris Regelbrugge. With a greatly reduced crew continuing the search, Hadaway's body was recovered on May 22, 2014, and Regelbrugge's body was recovered on July 22, 2014.
Obama's Visit
On Tuesday, April 22, 2014, a month after the landslide, President Barack Obama (b. 1961) visited the slide area. Along with Governor Inslee and U.S. senators Patty Murray (b. 1950) and Marie Cantwell (b. 1958), the president boarded a marine helicopter and flew over the area for about 15 minutes. A local TV station reported what he saw:
"Ripped up trees littered the landscape, and the path of the Stillaguamish River was altered. A one-mile section of Highway 530 was covered in mud and debris. A couple of bright yellow excavators could be seen operating below, digging in the earth as part of the ongoing effort to recover the bodies of those who died. Amid the wreckage, an American flag flew at half-staff" (KIROTV.com, April 22, 2014).
The president and his party then drove by motorcade through Arlington to Oso, where he spoke words of admiration and comfort to emergency responders, volunteers, and family members of victims.
Two days after the slide, on March 24, the president had directed aid to the region via a presidential emergency declaration, and in April he announced an additional $7.5 million in FEMA aid to supplement state, tribal, and local recovery efforts.
"Could It Have Been Foreseen?"
The short answer is, yes, it could have been foreseen. How do we know? Because it was foreseen.
Warnings about hazardous landslides in the area were regular and explicit. "[M]ultiple studies identified the potential for a 'catastrophic' failure affecting human safety and property," according to a 186-page report on the event issued on July 22, 2014, by the National Science Foundation-sponsored GEER, which stands for Geotechnical Extreme Events Reconnaissance (GEER Report, 54).
The land around Oso was formed during the last glacial advance into the Puget Sound lowlands, and its "glacially-derived sediments include interbedded layers of clay, silt, sand, gravel, cobbles, and boulders" (GEER Report, 159). These types of relatively loose sediments are extremely landslide-prone, particularly when the terrain is steep and saturated with water, as in the present case.
The geomorphic history of this part of the North Fork Stillaguamish River Valley is one of numerous large landslides over the past 6,000 years, some of which were as massive as the 2014 Oso slide. The GEER report states that the Oso landslide was a reactivation of an ancient landslide. The valley itself is made of old landslide debris.
In recent decades, landslides were warned against and predicted, and they actually occurred with fair regularity. A failure of the hillside in 1949 destroyed a half-mile of the riverbank. In 1951 another "large failure of the slope" occurred (Petley, "The Steelhead Landslide ...," March 25, 2014). In the 1950s terms such as "slide hill" and "mudflow creek" were commonly used to refer to the area.
On January 7, 1967, a large landslide "decimated Steelhead Haven," although no one was injured ("Oso Neighborhood ..."). This landslide flooded 48 lots and damaged or destroyed 25 cabins. Responding to it, Department of Natural Resources geologist Gerald W. Thorsen stated, "this slide has shown that major construction below any of these old scarps should be done with extreme caution" (quoted in GEER Report, 51). A 1999 report written on the area for the Army Corps of Engineers discussed the potential for a "large catastrophic failure" ("Scientists Predicted Deadly Washington Landslide").
A 2001 study by GeoEngineers carried out for the Stillaguamish Tribe of Indians stated, "Catastrophic failure potential places human lives and properties at risk" (quoted in GEER Report, 55).
The river's constant erosion of the toe of old landslide material and the addition of falling silt and sediment from the slope into the river was degrading the habitat for chinook salmon and steelhead, which are listed as threatened under the Endangered Species Act. In 2005 the Stillaguamish Tribe of Indians, which has treaty fishing rights in the river below the site of the Oso landslide, obtained funds to move the river channel 500 feet to the south (away from the hill). Before the work was done, the Hazel landslide moved the channel for them.
The Hazel landslide was a massive failure of the slope that occurred on January 25, 2006. It forced the North Fork Stillaguamish River into a new channel. Debris from this landslide traveled more than 300 feet but stopped short of the community of Steelhead Haven.
Following the Hazel landslide, the tribe constructed a 1,400-foot-long revetment (slope-retaining structure) made of five layers of logs chained together loosely (to provide flexibility for earth movement and settlement) with steel cables and anchored with cement blocks. This provided a noticeable improvement in salmon spawning. The revetment had to be repaired after the river eroded 10 feet back toward the slope.
In 2010 Snohomish County commissioned a report, in compliance with federal law, which stated that the hillside along the North Fork of the Stillaguamish "was one of those highlighted as most dangerous" ("2010 Study Ranked Area").
Building: "Very Safe"?
Notwithstanding the notorious instability of the high slope rising on the north side of the river, building permits continued to be issued for construction in Steelhead Haven. According to the GEER report:
"The portion of the valley directly below the slope and affected by the 2014 event contained 108 lots zoned for Single Family Residences. Some form of structure was located on 49 of the lots; 25 were occupied year round and 10 were occupied part time as vacation homes. The Steelhead Haven Plat was recorded in 1960. About one-half of the homes were built after 1996. After the 2006 landslide, five new homes were built in Steelhead Haven and two were built outside of it but within the area affected by the 2014 landslide" (GEER Report, 54).
In an article titled "Oso Neighborhood Never Should Have Been Built," The Seattle Times revealed that the original developer of Steelhead Haven, Genevieve Taylor (1917-2001), who began selling lots in the area in 1960, "failed to secure a required permit, avoiding a process that would have warned of the dangers of building there" ("Oso Neighborhood ...").
On the Monday after the disaster, John Pennington, head of the Snohomish County Department of Emergency Management, declared that "the hillside that collapsed had been considered 'very safe' and that the slide 'came out of nowhere'" ("2010 Study Ranked Area").
"Don't tell me, please," responded Timothy Egan in an op-ed in The New York Times, that nobody saw one of the deadliest landslides in American history coming" ("A Mudslide, Foretold").
Causes of the Oso Landslide
It was quickly determined that a small earthquake that occurred on March 10 did not cause the slide. It was likely caused by a confluence of events and situations.
The GEER report asserts that the landslide occurred in two distinct stages, the first at 10:37 a.m., the second at 10:41 a.m. A United States Geological Survey report from Vancouver, Washington, based on seismic data, disagrees with this, arguing that "all the important action appears to have been compressed into a rapid chain reaction in the first few minutes" ("Scientists Trot Out Dueling Analyses of Deadly Landslide"). According to the GEER report, groundwater was at the crux of the failure. Although the winter season before March had been relatively dry, three weeks of extreme rainfall preceded the event. However, no other Snohomish County slope failed. The rain likely contributed to the landslide but did not by itself cause it.
Groundwater involves more than just rain.
The 2006 landslide caused a drop in elevation at its head, which may have created a change in the flow of groundwater, causing more water to flow into the landslide area. The 2006 landslide also made the gradient of the hill flatter and more hummocky, causing decreased runoff and increased saturation of the landslide area.
What about logging? Although the specific hillside that failed had not been logged since the 1950s, and although the GEER report states that evaluating the effects of logging "is beyond the scope of this report," the report also notes that Whitman Bench, the forested plateau above the landslide slope, "which is a source area for groundwater that seeps towards the slope, has harvested tracts in various stages of growth. It is possible that in 2014, the location, size and maturity of growth in these tracts was such that groundwater discharge to the slope was greater in 2014 than in previous years ..." (GEER Report, 129). The Seattle Times reported that the Department of Natural Resources had permitted logging in 2004 in an area above the slide, using an outdated map, and that if a more current map had been used "regulators likely would have restricted most of the 7.5 acres that were clear-cut in 2004" ("State to Scrutinize ...").
Static liquefaction of the 2006 (and earlier) landslide mass was likely. Landslide deposits, no longer compacted by material above them, are loose, with low density. This enables water to seep between individual grains of sand so that the material begins acting like water and flowing, a state called liquefaction. Liquefaction spells disaster; it will cause a slope to fail. It is well known, the GEER report states, that "loose materials subjected to the static shear stress states imposed by a slope [shear stress is the force of a fluid acting on a body in its path] can liquefy in response to even very minor increases ... in shear stress" (GEER Report, 130). While inspecting the site, the GEER team observed sand boils (water appearing to boil up from sand), a sign of liquefaction.
Landslides themselves incorporate water, and they can take a very long time to dewater while of necessity taking in even more water from rain and from new flows of groundwater. There was not much time between the 2006 Hazel landslide and the 2014 slide for dewatering of the earlier landslide to occur. "These areas will continue to drain but additional rainfall and infiltration will also occur. It could be many years before the groundwater regime in the slide mass is at an equilibrium state, uninfluenced by the water it incorporated in a prior landslide event" (GEER Report, 131).
A related cause was, as reported in technical language, "Dilation and strain softening on the pre-existing shear surfaces and elsewhere in the glacial lacustrine unit" (GEER Report, 130). The "glacial lacustrine unit" is part of the slope that was deposited by a glacial lake. "Shear surfaces" are surfaces discontinuous with adjacent material, caused by previous landslides. These lacustrine deposits are in an over-consolidated state on the slope because the weight of the glacier went away and because of erosion of overburden. Thus, when shear stress (the force of groundwater) arrives, the material dilates and becomes looser and weaker. This process of loosening or softening can go on for years, progressing from one part of the slope to another "before the overall slope becomes too weak to support itself, and falls" (GEER Report, 130).
One question is to what extent the river was eroding the toe of a previous landslide. The toe of a landslide supports the material above it. If it is eroded away, the hill can fall.
Finally, it's possible that by being only a little larger and by starting only a little higher on the slope, the landslide managed to entrain the river along with saturated valley alluvium (loose soil and sediments) and in this way gained the tremendous force to travel farther across the valley, far enough to overwhelm the small community of Steelhead Haven.
Aftermath, Continuing ...
After assisting in the rescue and recovery of people, and coming to the aid of families, the Washington Department of Fish and Wildlife along with fish managers from the Stillaguamish Tribe of Indians and Tulalip Tribes began measuring the effects of the landslide on fish. The landslide put at risk several runs of wild steelhead and salmon that spawn in the North Fork Stillaguamish River or in its tributary creeks. Three populations -- chinook, steelhead, and bull trout -- are listed as threatened under the Endangered Species Act. In the landslide, fish were buried and stranded, their migration passages blocked, their gills fouled by silt in the river. The measurements and assessments of the fish and their damaged riparian habitat were expected to continue for years.
Transportation became another emergency. With SR 530, the primary highway route from Darrington west to the populous Interstate-5 corridor, temporarily severed, the Washington State Department of Transportation immediately opened the Mountain Loop Highway, ordinarily still closed for the winter. That route, which included a 14-mile section of one-lane gravel road, provided a way, however potholed and bumpy, to get to Darrington via Granite Falls. Another way to get from Darrington to Everett or other cities in the I-5 corridor was to go north on SR 530, west on SR 20, and south on Interstate 5. Both were long ways around, increasing commute times and gas expenses for people getting to work. Mud and debris was removed from Highway 530 and by late May a slow, highly monitored one-lane passage opened. A new section of the road, elevated to avoid flood damage, was planned to be open by October 2014.
On July 25, 2014, Governor Inslee and Snohomish County Executive John Lovick appointed a commission of 12 to study how to better avoid and respond to landslides in the future. The commission was asked to study how to avoid such disasters in the future, not to assign accountability, which would be done by the courts.
As of September 2014, at least 19 legal claims had been filed against Snohomish County and the state on behalf of victims. Precursors to law suits, they involved allegations of wrongful death, among other allegations. They argued that residents were not adequately warned about the dangers of a landslide. They also questioned whether logging permitted by the Department of Natural Resources was a factor in the disaster.
