John Pennington, head of the department of emergency management, told reporters residents of the area knew the risks.
“We did everything we could do. Sometimes big slides happen,” he said. “I’m not sure that we could have been more prepared to prevent a landslide of this magnitude.”
The slide Saturday buried a square mile in the village of Oso, covering 49 buildings and part of a highway. While the official death toll Wednesday was 16, about 175 people remained unaccounted for.
Washington Gov. Jay Inslee said the death toll is certain to increase a lot. He said buildings and cars gave those hit by the mud little protection.
"The force of this landslide just defies imagination. The cars that have been found have been just, literally, twisted into corkscrews and torn in half," Inslee said in an interview with CNN.
The governor said investigators will examine whether there were early warnings of the disaster that could have reduced its impact.
Critics say home construction should have been banned in the area on the North Fork of the Stillaguamish River. Pennington said measures taken after a major slide in 2006, which caused no deaths, had prevented smaller ones.