Landslide expert Richard Iverson estimates the Oso mudslide crashed into the community at about 60 miles per hour.
Iverson's computer model indicates the March 22 slide traveled faster and farther than expected. The slide off a 600-foot bluff ran out nearly a mile.
Iverson told The Seattle Times he hopes his study of the slide helps determine what caused the slide to liquefy so quickly. That information could be used to identify other landslide danger zones.
Iverson works from the U. S. Geological Survey's Cascades Volcano Observatory in Vancouver.