Blocked river trickling through massive mud wall in deadly Washington landslide

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Authorities say water that built up behind a massive deadly mudslide in Washington state is slowly trickling downstream.

Snohomish County sheriff's office spokeswoman Shari Ireton says officials confirmed Sunday that the Stillaguamish River is breaking through the wall of mud and debris that has blocked it since Saturday's landslide.

The square-mile of mud raised concerns about potential flooding downstream of Oso, about 55 miles north of Seattle. Officials say they don't think the water would suddenly burst.

Eighteen people were unaccounted for a day after the landslide killed three people, injured several others and destroyed as many as 30 homes.

The National Weather Service extended a flash flood watch into Monday afternoon. Gov. Jay Inslee said Sunday there were no plans to move the debris blocking the river.