Ongoing movement of the huge landslide that crashed down on a rural Northwest Washington neighborhood on Saturday is hampering the search for more victims.
Some ground search and rescue crews were pulled back Monday because of signs of instability on the hillside and debris field near Oso, Snohomish County.
State geologist Dave Norman of Washington's Department of Natural Resources says, "It is not unusual after a landslide like this to see additional movement." Norman briefed reporters after flying over the disaster area for a second day.
Norman says right now, the debris avalanche is still "visibly moving." Because of that, the geologist judges "it is prudent" for rescuers to wait to fan out on foot in the muck.
Norman says he doesn't know how long it will take for the mud and debris to settle. Dozens and dozens of people remain unaccounted for, potentially buried as much as 15 feet deep.