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.

What type of landslide was the Oso landslide?

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.

How fast was the Oso slide estimated to have moved?

USGS research indicates that the landslide’s average speed was about 40 miles per hour, with maximum speeds likely even higher. The area overrun by the landslide was about one half square mile, and the landslide moved about 18 million tons of sand, till, and clay.

How long did the Oso landslide last?

approximately 2.5 minutes
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 happened in 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.

Could the Oso landslide 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 people died during the Oso mudslide?

43 people
Pain still raw 7 years after Oso slide – Monday, March 22 marks the seven-year anniversary of the deadly Oso landslide, which killed 43 people in 2014.