The hillside which collapsed and produced a March 22, 2014 mudslide near Oso, Washington, is seen in this March 23, 2014 handout photo.
The death toll from the landslide that hit a US town last month rose to 33 on Monday, authorities said.
The Snohomish County medical examiner's office said all but three have been identified.
Many died of multiple blunt force injuries in the March 22 slide that crushed a residential area in Washington state.
The number of missing on Monday was 12, said Shari Ireton, spokeswoman for the Snohomish County sheriff's office.
However, that figure does not necessarily correlate with the number of dead, said Kelly Stowe, a spokeswoman for the medical examiner's office. The missing list remains fluid as names are added and removed.
As the search continues in the debris for bodies, the Army Corps of Engineers is working on a berm - a rock and gravel barrier - to prevent the river from flooding parts of the debris field. Engineers hope to finish berm in a week.