Updated

Officials in Washington state said Monday that the death toll from last month's mudslide in the town of Oso had risen to 33, with all but three of the bodies identified by the Shohomish County medical examiner's office.

The latest name added to the list is Billy L. Spillers, 30, of Arlington. Like the others, he died of multiple blunt force injuries in the March 22 slide that crushed the residential area along the North Fork of the Stillaguamish River about 55 miles northeast of Seattle.

His name had been on the list of missing.

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.

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Spillers was a Navy chief petty officer who lived with his wife, Jonielle, and their four children. She was at her nursing job when the landslide hit their house. Spillers' 4-year-old son survived and was rescued by a helicopter.

Spillers' daughter Kaylee, 5, and stepson Jovon Mangual, 13, have been identified among the dead. Two-year-old daughter Brooke is listed among the missing.

So far, more than 220 people have registered with the Federal Emergency Management Agency, seeking individual assistance, FEMA spokesman David Mace said Monday as he announced the opening of three disaster recovery centers for slide victims.

FEMA workers and state representatives will provide "one-on-one, face-to-face counseling and assistance" at the centers in Arlington, Darrington and at the Oso fire station, Mace said.

As the search continues in the debris for bodies, the Army Corps of Engineers is working on a berm -- a big rock and gravel barrier. That will enable crews to pump water over the berm and drain an area where search teams want to work, said Steve Thomsen, county public works director. Engineers hope to finish the berm in a week.

A forecast of warmer and mostly drier spring weather this week should help. But rain showers Tuesday will cause the river to rise about a foot in the pool formed by the mudslide, the National Weather Service said. That's 2 or 3 feet below the high reached on March 30.

Highly sensitive instruments newly placed on the landslide mass and nearby hillside provide real-time measurement of even tiny earth movements, said Rick LaHusen of the U.S. Geological Survey. So far, scientists have seen "nothing that gives us any concern" for the safety of search crews.

The Associated Press contributed to this report.