Science Center Objects
Although they are relatively uncommon, large catastrophic landslides move rapidly destroying everything in their paths. Such landslides are difficult to predict as shown by the following examples.
The SR530 landslide near Oso, Washington had historically moved short distances, but in March 2014, it failed catastrophically and crossed the entire Stillaguamish River Valley, killing 43 people. The La Conchita landslide in California persistently moved slowly in 1995, and then moved very rapidly in 2005, killing 10 people who could not escape their homes before they were buried. Although previously studied by many scientists, this catastrophic movement was not forecast. The 1996 Dodson debris flow in the Columbia River Gorge in Oregon initiated from runoff and small landslides with volumes of less than several hundred cubic meters but grew by entrainment of channel sediment to more than 25,000 cubic meters before impacting residences, a rail line, and Interstate 84 on the debris fan about 1.5 km from the initiation location. Ongoing research aims to improve understanding of factors and mechanisms that control the locations, timing, extent, and speed of large, potentially catastrophic landslides.