What triggered the Oso landslide?
Oso mudslide and recovery timeline 1900s – Seasonal high water begins eroding the hill that eventually gave way in the 2014 mudslide. The Stillaguamish River channel pushes north. 1930s to 1950s – Logging is the economic engine of the Oso area. Some of the logged area is sensitive to shifting because of groundwater.
How far did the Oso landslide travel?
The landslide killed 43 people as it plowed through the Steelhead Haven neighborhood. When it stopped, after crossing the river, the neighborhood, and State Route 530, the Oso landslide had traveled 1.4 kilometers. That’s a remarkable distance, says Brian Collins of the USGS, given the geologic and geographic context.
What type of landslide was the Oso slide?
The landslide involved a complex sequence of events—including rotation, translation, and flow mechanisms—and can be referred to as a debris-avalanche flow. Studies indicate that slope failure occurred in two stages over the course of about 1 minute.
What happened during the Oso landslide?
Landslide debris blocked the North Fork Stillaguamish River, destroyed about 40 homes and other structures, and buried nearly a mile of State Route 530. Most tragically, it caused 43 fatalities in the community of Steelhead Haven near Oso, Washington. Oso was emblematic of a worst-case landslide scenario.
Why was the Oso landslide an unusual landslide?
The Hazel Landslide has a history of instability dating to 1937. Prior to the March 2014 mudslide, the Oso area had heavy rainfall during the previous 45 days, up to 200 percent of normal. A national geologist stated the flow of the landslide was extreme because of the extraordinary run-out of mud and debris.
What happened during the OSO landslide?
Could the disaster at Oso Washington have been prevented?
Landslide-risk mapping alone could not have prevented the Oso tragedy. Only direct actions such as investing in hillside stabilization or keeping individuals out of harm’s path could have done that.
How many died in Oso landslide?
41
2014 Oso mudslide/Number of deaths
Where exactly was the Oso landslide?
northwest Washington state
The Oso landslide, also known as the SR 530 landslide, occurred in northwest Washington state on March 22, 2014, leading to devastating loss of life and destruction of property.
When did the Oso slide happen?
March 22, 2014
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….2014 Oso mudslide.
| Oso mudslide on March 29, 2014, view to the northeast | |
|---|---|
| Date | March 22, 2014 |
| Location | Oso, Washington |
What happened to SR 530 Oso slide?
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. SR 530 begins at a diamond interchange with I-5 at Island Crossing in Arlington, near the freeway’s bridge over the Stillaguamish River.
What time of day did the Oso landslide happen?
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.
What is the history of the Hazel Landslide?
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.
What happened in the 2014 Steelhead Haven landslide?
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.