2014 Oso mudslide
Oso mudslide on March 29, 2014, view to the northeast
|
|
| Time | 10:37 a.m. |
|---|---|
| Date | March 22, 2014 |
| Location | Oso, Washington |
| Coordinates | 48°16′57″N 121°50′53″W / 48.28256°N 121.84800°WCoordinates: 48°16′57″N 121°50′53″W / 48.28256°N 121.84800°W |
| Cause | Suspected soil saturation from heavy rainfall |
| Deaths | 43 |
| Non-fatal injuries | 4 serious |
| Missing | 0 |
| Property damage | 49 homes and other structures destroyed |
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.
The March 2014 landslide engulfed 49 homes and other structures in an unincorporated neighborhood known as "Steelhead Haven" 4 mi (6.4 km) on the south side of the North Fork of the Stillaguamish River, 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), approximately 15 miles (24 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.
...
Wikipedia