Report: Liquefaction Had a Hand in Deadly Washington Mudslide

A study of the Oso landslide in Washington state that killed 43 people in March says the amount of water that saturated a hillside made it especially destructive when it gave way.

The soil lost its coherence and flowed like a liquid in a process called liquefaction.

The Daily Herald reported the study was published last week by U. S. Geological Survey hydrologist Richard Iverson who is based at the Cascades Volcano Observatory in Vancouver.

The slide occurred on a dry day during one of the wettest winters on record in the area.