A major landslide occurred 4 miles (6.4 km) east of Oso, Washington, United States, on March 22, 2014, at 10:37 a.m. local time. A portion of an unstable hill collapsed, sending mud and debris to the south across the North Fork of the Stillaguamish River, engulfing a rural neighborhood, and covering an area of approximately 1 square mile (2.6 km2). Forty-three people were killed and 49 homes and other structures destroyed.
|2014 Oso mudslide|
Oso mudslide on March 29, 2014, view to the northeast
|Date||March 22, 2014|
|Cause||Suspected soil saturation from heavy rainfall|
|Non-fatal injuries||4 serious|
|Property damage||49 homes and other structures destroyed|
The March 2014 landslide engulfed 49 homes and other structures in an unincorporated neighborhood known as "Steelhead Haven" on the south side of the North Fork of the Stillaguamish River, approximately 4 miles (6.4 km) east of Oso, Washington. It also dammed the river, causing extensive flooding upstream as well as blocking State Route 530, the main route to the town of Darrington (population 1,347), 16 miles (26 km) east of Oso.
The natural rock and mineral formation (referred to by geologists as a "geological feature") with the most recent activity in the area of Oso is known as the Hazel Landslide; the most recent landslide event was referred to in the media as "the Oso mudslide." Excluding landslides caused by volcanic eruptions, earthquakes or dam collapses, the Oso slide is the deadliest single landslide event in United States history.
The Hazel Landslide has a history of instability dating to 1937. Prior to the March 2014 mudslide, the Oso area had had heavy rainfall during the previous 45 days, up to 200 percent of normal. The slide, described by witnesses as a "fast-moving wall of mud," contained trees and other debris; it cut through homes directly beneath the hill on the south side of the Stillaguamish River. A firefighter at the scene stated, "When the slide hit the river, it was like a tsunami". A Washington state geologist stated the slide was one of the largest landslides he had personally seen. The mud, soil and rock debris left from the mudslide covered an area 1,500 ft (460 m) long, 4,400 ft (1,300 m) wide and deposited debris 30 to 70 ft (9.1 to 21.3 m) deep. A national geologist stated the flow of the landslide was extreme because of the extraordinary run-out of mud and debris. While the landslide was well documented, a research team from the Geotechnical Extreme Events Reconnaissance (GEER) announced in April 2014 that it would investigate the factors contributing to the slide.
More than 100 first responders from Snohomish County and other surrounding counties were dispatched to assist with emergency medical and search-and-rescue efforts, including the Navy's search and rescue unit stationed at nearby Naval Air Station Whidbey Island. Over 600 personnel, including more than 160 volunteers, worked on landslide recovery operations.
Late in the evening of March 22, 2014, Washington's Lieutenant Governor Brad Owen declared a state of emergency in Snohomish County. Washington state Governor Jay Inslee toured the area by air the following day before joining county officials at a news conference.
On the day of the slide, eight people were rescued and taken to regional hospitals. While the official search for victims ended in April 2014, workers and volunteers continued to screen debris and look for one victim still unaccounted for. On July 22, 2014 the Snohomish County Sheriff's Office confirmed 43 fatalities after remains of the final victim had been located and identified.
The slide blocked the North Fork of the Stillaguamish River, causing it to back up eastward. Because of concerns that the mud and debris dam could fail and cause downstream flooding, the National Weather Service (NWS) issued a flash flood watch. On April 2, 2014, with the river flowing in a new channel at the north end of the debris dam, the service lifted the flash flood watch. Flooding due to the partially obstructed river continued to occur upstream of the debris dam. As a result, the NWS continued to issue flood warnings for the Stillaguamish one month after the March 2014 slide.
State Route 530 was indefinitely closed after the slide by the Washington State Department of Transportation (WSDOT), with an alternative local route opened the following week after snow was cleared from the unpaved portion of Mountain Loop Highway south of Darrington. The highway was cleared enough by May 31 to open one lane of escorted traffic. Because the highway was badly damaged, and because the topography of the area had been altered by the landslide, WSDOT decided to elevate that section of the highway when it was rebuilt. As of July 27, the first of four stages in rebuilding the highway had been completed. The new roadway was opened September 22, ahead of schedule of the projected completion date of early October 2014.
On April 3, the mudslide was declared a major disaster by President Barack Obama. The declaration was requested on April 1 by Governor Inslee, who stated that approximately 30 families needed help with housing and other needs. Inslee said that financial loss estimates had reached $10 million. Snohomish County Emergency Management Director John Pennington advised residents to register with FEMA. Four days later, during passage of the Green Mountain Lookout Heritage Protection Act, Senator Patty Murray (D-WA) mentioned the landslide, saying the bill would "provide a glimmer of hope for the long-term recovery of this area."
On April 22, President Obama visited the west side of the slide area. After arriving in Air Force One at Paine Field in Everett, he met with officials and boarded Marine One. There, he was joined by Governor Inslee and Senators Patty Murray and Maria Cantwell as well as Rep. Suzan DelBene for a flyover of the slide and debris field. After viewing the site, the president met privately with survivors, families of the victims, and some of the scene's first responders and rescuers at the Oso fire hall.
On March 24, two days after the slide, John Pennington, Director of Snohomish County's Department of Emergency Management, stated at a news conference, "This was a completely unforeseen slide. This came out of nowhere." The same day The Seattle Times published an article about previous slides at the same location, as well as the likelihood of future slides. The article contained comments from geologists, engineers, and local residents, and stated that the area was known among locals as "Slide Hill". On the next day, The Times followed up with a full page article, "'Unforeseen' risk of slide? Warnings go back decades." Snohomish County Public Works Director Steve Thomsen was quoted as saying, "A slide of this magnitude is very difficult to predict. There was no indication, no indication at all."
On March 27, 2014, The Seattle Times reported that a 2010 study, commissioned by the county, warned the hillside above Steelhead Drive was one of the most dangerous in the county. According to Rob Flaner, one of the authors of the 2010 report, "For someone to say that this plan did not warn that this was a risk is a falsity." In the days following the slide, criticism of Snohomish County officials received national attention in a New York Times editorial. The Seattle Times further reported that in 2004, county officials became concerned about the possibility of a dangerous landslide in the Steelhead Haven area, and considered buying out the homes of that area's residents. The idea was rejected with the county building a new wall in an attempt to stabilize the slope. Some disaster experts criticized this decision as a serious mistake. According to environmental engineer and applied geomorphologist Tracy Drury, "[after the 2006 slide they] didn't even stop pounding nails." As to any kind of buy-out program, Drury further stated, "I think we did the best we could under the constraints that nobody wanted to sell their property and move elsewhere."
Repairs to the slide area extend back several decades prior to the March 2014 slide. A rock revetment installed in 1962 to protect the toe of the slide area from erosion from the river was overrun by a slide two years later. An effort in 2006 to move the river 430 feet (130 m) south of the erosion area failed when another landslide moved the river a total of 730 feet (220 m).
In the days following the slide, scientists questioned whether logging in the area could have been a factor contributing to the hillside collapse. Grandy Lake Forest Associates of Mount Vernon, Washington proposed a 15-acre (6 ha) clearcut at the upper edge of the Oso landslide zone in 2004. Washington state forester Aaron Everett stated in an interview with KUOW that the application was rejected and "The one that was approved in the end eliminated the part of the harvest that would have been inside the groundwater recharge area." Everett further stated the resulting 7-acre (2.8 ha) clearcut operation reached to the edge of the groundwater danger zone. An investigation is being conducted to determine whether Grandy Lake crossed into the restricted area that could theoretically feed groundwater into the landslide zone, affecting it for 16 to 27 years.
Two years after the mudslide, about 11,000 tons of wreckage had been removed from the slide area. 34 parcels of land had been purchased by Snohomish county from owners of property too dangerous for residences. Properties in the area bordering State Route 530 and across from the slide area remained salable.
In October 2016, survivors and the victims' families reached settlements with the State of Washington and a timber company, Grandy Lake Forest Associates, for $50 million and $10 million respectively.
Alongside State Route 530, the entrance to what was Steelhead Drive is closed by a gate that was decorated by impromptu memorials. Alongside, three rows of 43 cedar trees were planted, one for each of the victims. At the time of the planting, each tree was decorated with mementos specific to each person.
In September 2017, one of the few trees in the path of the slide that remained standing near Highway 530 and was seen by locals as a memorial, was cut down as a danger tree. County officials decided to cut the Sitka spruce tree down after it was determined its roots had sustained enough damage that it could no longer be considered stable and not a hazard to both the Whitehorse Trail parallel to the highway as well as the highway itself. Following the slide, a memorial sign carved out of cedar and reading, "Oso. 10:45 a.m. 3/22/14", was placed on the spruce and remained until the tree was removed. The Snohomish County Department of Parks, Recreation & Tourism announced on March 22, 2018 that plans had begun for a permanent memorial commemorating the victims. The tribute is set to be built at the location of the slide and fundraising efforts are underway with wood from the formerly standing memorial tree to be repurposed and used for the permanent display.
Ground vibrations generated by the Oso landslide were recorded at several regional stations and subsequently analyzed by the Pacific Northwest Seismic Network (PNSN). The initial collapse began at 10:37:22 a.m. local time (PDT; 17:37:22 UTC), lasting approximately 2.5 minutes. Debris loosened by initial collapse is believed to contain material previously disturbed and weakened by the 2006 slide. Following the initial event was another large slide occurring at 10:41:53 PDT.
Additional events, most likely smaller landslides breaking off the head scarp, continued for several hours. The last notable signal came at 14:10:15. Examination of records from the nearest seismic station 7 mi (11 km) to the southwest indicate small seismic events started around 8 a.m. the day of the slide and stopped in the late afternoon. However, they were not detected at the next nearest seismic station. They are also seen in the days before and after the slide, but only during daylight hours. They are believed to be related to some kind of human activity. No other indications of possible precursors have been found.
In the days following the slide, Snohomish County Emergency Management Director John Pennington speculated a 1.1 magnitude earthquake on March 10 may have triggered the landslide. Data collected by the PNSN shows a magnitude 1.1 earthquake on that date in the vicinity of the Oso landslide (about 2 ±0.8 km to the northeast), at a depth of 3.9 ±1.9 km. Regardless, the United States Geological Survey (USGS) determined the slide was not caused by seismic activity.
The landslide occurred at the southeastern edge of Whitman Bench, a land terrace about 800 ft (240 m) above the valley floor and consisting of gravel and sand deposited during the most recent glaciation. When the Puget Lobe of the Cordilleran Ice Sheet moved south from British Columbia, Canada filling the Puget Lowland, various mountain valleys were dammed and lakes were formed. Sediment washed down from the higher mountains settled in the lake bottoms, forming a layer of clay.
As the glacial ice pressed higher against the western end of Mount Frailey, water flowing around the edge of the ice from the north was forced around the mountain, eventually pouring in through the long valley extending to the northwest and now occupied by Lake Cavanaugh. Sand and gravel carried by the flow and entering the glacial lake dropped out to form a delta, the remnant of which is now known as Whitman Bench.
Following the glacier's retreat and allowing for the lake to be released, the river carved out most of the clay and silt deposits, leaving the former delta "hanging" approximately 650 ft (200 m) above the current valley floor When the sand portion of a deposit has very little clay or "fines" to cement it together, it is structurally weak, leaving the area around it vulnerable. Such an area is also sensitive to water accumulation, increasing the internal "pore" pressure and subsequently contributing to ground failure. Water infiltrating from the surface will flow through the surface, save for contact with the less permeable clay, allowing the water to accumulate and form a zone of stability weakness.
Such variations in pore pressure and water flux are one of the primary factors leading to slope failure. In case of the area of the Stillaguamish River where the March 2014 slide occurred, erosion at the base of the slope from the river flow further contributes to slope instability. Such conditions have created an extensive series of landslide complexes on both sides of the Stillaguamish valley. Additional benches on the margin of Whitman Bench are due to deep-seated slumping of large blocks, which also creates planes of weakness for future slippage and channels for water infiltration.
The Hazel landslide has been active for over half a century. Thorsen (1996) noted a tight river bend impinging on the north bank with active landslides visible in 1937 aerial photographs. The next 60 years involves two periods of relatively low landslide activity, and two periods of relatively high activity, the last of which extends to this day .
Known activity at this specific site includes the following:
Broken or incomplete references
On 13 December 2014, a landslide in Banjarnegara, Central Java, Indonesia, killing 93 with 23 people missing. The disaster occurred on Jemblung Village in Banjarnegara, Indonesia, at Friday, around 03.00 p.m. At the time, most of the villagers were taking a nap on their houses. The landslides also trapped some vehicles on the road. Amateur video caught the moment when a large piece of the mountain fell to the whole village. Indonesian authority said that at least around 100 people are feared dead and 300 houses were destroyed.Jemblung village took a direct hit from the landslides. Jemblung Village is a place where 300 residents live. Around 200 people survived the disaster, another a hundred people didn't, which represents a third population of the village who didn't come out alive.The 2014 Banjarnegara landslide was one of the worst and deadliest landslide in Indonesia since 2006. Indonesian official concluded that heavy rain were blamed for the mass human life loss, although human error were also a prime suspect. As the result of the tragedy, the Indonesian government began inspecting all regencies and district on high-risk area, particularly Banjarnegara itself.2014 in the United States
Events in the year 2014 in the United States.2018 Southern California mudflows
A series of mudflows occurred in Southern California in early January 2018, particularly affecting areas northwest of Los Angeles in Santa Barbara County. The incident was responsible for 23 deaths, although the bodies of two victims were not found. Approximately 163 people were hospitalized with various injuries, including four in critical condition. The disaster occurred one month after a series of major wildfires. The conflagrations devastated steep slopes, which caused loss of vegetation and destabilization of the soil and greatly facilitated subsequent mudflows. The mudflows caused at least $177 million (2018 USD) in property damage, and cost at least $7 million in emergency responses and another $43 million (2018 USD) to clean up.Airlift Northwest
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Chance McKinney is a country music artist from Seattle, Washington. In 2009, while working as a math teacher at Kamiak High School, he entered and won Country Music Television's Music City Madness competition for unsigned artists.Community Transit
Community Transit (CT) is the public transit authority of Snohomish County, Washington, United States, excluding the city of Everett, in the Seattle metropolitan area. It operates local bus, paratransit and vanpool service within Snohomish County, as well as commuter buses to Downtown Seattle and the University of Washington campus. CT is publicly funded, financed through sales taxes, farebox revenue and subsidies, with an operating budget of $133.2 million. The entire agency carried more than 10 million passengers in 2015, placing it fourth among transit agencies in the Puget Sound region. The city of Everett, which serves as the county seat, is served by Everett Transit, a municipal transit system.
Community Transit, officially the Snohomish County Public Transportation Benefit Area Corporation (SCPTBA), operates a fleet of 225 accessible buses, 54 paratransit vehicles, and 412 vanpool vans, maintained at two bus bases located in the Paine Field industrial area in Everett. Service is provided year-round at 1,500 stops on 46 routes throughout the county public transportation benefit area (PTBA). CT began operation as SCPTBA Public Transit on October 4, 1976, four months after the third attempt to establish public transit in Snohomish County was approved. Renamed Community Transit in 1979, the agency expanded service in its first decades of existence, later taking over King County Metro commuter routes to Seattle in 1989 and adding several cities into its PTBA in the 1980s and 1990s. CT service hours fell during two funding crises in the 2000s, after the passage of Initiative 695 in 1999 and during a severe recession from 2010 to 2012. Despite the cuts, which forced service hours to fall short of rising demand, the agency debuted the state's first bus rapid transit line, Swift, as well as introducing "Double Tall" double-decker buses on its commuter routes to Seattle.FEMA Urban Search and Rescue Task Force
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There are 28 Task Forces in the United States, each sponsored by a local agency. In the event of a disaster in the United States, the nearest three Task Forces will be activated and sent to the site of the disaster. If the situation is large enough, additional teams will be activated.John S. Tuohy
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The term landslide or less frequently, landslip, refers to several forms of mass wasting that include a wide range of ground movements, such as rockfalls, deep-seated slope failures, mudflows, and debris flows. Landslides occur in a variety of environments, characterized by either steep or gentle slope gradients, from mountain ranges to coastal cliffs or even underwater, in which case they are called submarine landslides. Gravity is the primary driving force for a landslide to occur, but there are other factors affecting slope stability that produce specific conditions that make a slope prone to failure. In many cases, the landslide is triggered by a specific event (such as a heavy rainfall, an earthquake, a slope cut to build a road, and many others), although this is not always identifiable.Landslide dam
A landslide dam or barrier lake is a natural damming of a river by some kind of landslides, such as debris flows and rock avalanches, or by volcanic eruptions. If the damming landslides are caused by an earthquake, it may also be called a quake lake. Some landslide dams are as high as the largest existing artificial dam.List of disasters in the United States by death toll
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Mount Higgins is a 5,176 ft mountain at the western edge of the North Cascades Range, in Skagit County of Washington state. Mount Higgins has two subsidiary summits, 4,986 ft Skadulgwas Peak, the fin-shaped middle peak, and also 4,849 ft Mount Higgins Lookout Site, the western sub-summit. The mountain is set on land administered by the Mount Baker-Snoqualmie National Forest. Mount Higgins is located along the north side of State Route 530, mid-way between the communities of Darrington and Oso, near the site of the 2014 Oso mudslide. The nearest higher peak is Round Mountain, 0.93 miles (1.50 km) to the north-northeast. Precipitation runoff from Mount Higgins drains into tributaries of the Stillaguamish River.Patty Murray
Patricia Lynn Murray (born Patricia Johns; October 11, 1950) is an American politician serving as the senior United States Senator from Washington, a seat she was first elected to in 1992. A member of the Democratic Party, Murray is Washington State's first female U.S. Senator.
She served as the Senate Majority Conference Secretary from 2007 until 2017, which made her the fourth-highest-ranking Democrat and the highest-ranking woman in the Senate. In 2017, Murray became the Senate Assistant Democratic Leader, making her the third-highest-ranking Democrat and still the highest-ranking woman in the Senate. Murray chaired the Democratic Senatorial Campaign Committee from 2001 to 2003, and again from 2011 to 2013. Murray chaired the Senate Budget Committee from 2013 to 2015. She also previously served as co-chair of the United States Congress Joint Select Committee on Deficit Reduction. Since January 2015, Murray has been the Ranking Democratic Member on the Senate Committee on Health, Education, Labor, and Pensions. She is currently the 6th most senior member of the United States Senate, the 3rd most senior Democrat, and the dean of Washington's congressional delegation.
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State Route 530 (SR 530) is a state highway in western Washington, United States. It serves Snohomish and Skagit counties, traveling 50.52 miles (81.30 km) from an interchange with Interstate 5 (I-5) southwest of Arlington past SR 9 in Arlington and Darrington to end at SR 20 in Rockport. Serving the communities of Arlington, Arlington Heights, Oso, Darrington and Rockport, the roadway travels parallel to a fork of the Stillaguamish River from Arlington to Darrington, the Sauk River from Darrington to Rockport and the Whitehorse Trail from Arlington to Darrington.
The first segment of SR 530 to appear on a map was a road extending from Arlington to Oso in 1899. The first segment to be state-maintained was Secondary State Highway 1E (SSH 1E), which ran from Conway to Arlington. SSH 1E was extended to Darrington in 1957 and later renumbered to SR 530 in 1964; the road was extended to Rockport in 1983 and later the route from Conway to I-5 was removed from the system in 1991. A section of the highway was destroyed in the 2014 Oso landslide and was rebuilt; a longer portion of SR 530 was designated the Oso Slide Memorial Highway in 2019.Whitehorse Trail
The Whitehorse Trail is a rail trail in northern Snohomish County, Washington, connecting the cities of Arlington and Darrington. The 27-mile-long (43 km) trail uses a former Northern Pacific Railway spur built in 1901 and abandoned in 1990. The trail has been in development since the county government purchased it in 1993, with some sections open to the public.
The trail's name is derived from the "Whitehorse Express", the historic name of the railroad, which in turn was named for Whitehorse Mountain.