March 22 will be the one year anniversary of the devastating Oso mudslide that killed 43 people in Washington. More than 10.8 million cubic yards of material, moving at about 60 mph, crossed the river, blasted through Steelhead Haven and sloshed back when it reached higher ground on the far side of the valley.
In this article in HeraldNet Jonathan Godt, landslide coordinator for the U.S. Geological Survey notes that the main question is why the slide traveled so far and so fast across the valley. They would like to use lidar to get a better understanding of the conditions, but the funding has not been approved.
In addition, more drilling in and around the slide zone to understand the three-dimensional structure of the collapsed hillside, more carbon-dating of other known landslides in the valley, and more study of the groundwater and how it moves through the hillside are needed.