Washington mudslide: before and after

In an area with loose glacial topsoil and a history of landslides, heavy rainfall can saturate the loose soil and cause it to become unstable. It liquifies, gravity takes over and it flows down, taking everything in its path with it. Below are images and maps of the area near Oso, Wash., in Snohomish County in before and after the disaster. Some of the buildings in the path of the mudslide are shown in red. Officials say about 50 buildings and structures were damaged. What made the mountain move.