This photo provided by the Washington State Patrol shows the aftermath of a mudslide that moved a house with people inside in Snohomish County in Washington State on Saturday.
Officials survey a large mudslide in this handout photo provided by the Washington State Police near Oso, Washington on Sunday.
A view of the hillside that gave way and collapsed near State Route 530 is seen in this Washington State Department of Transportation handout picture taken near Oso, Washington on Sunday.
This post was last updated at 8:20 p.m. ET.
A massive mudslide in Oso, Wash., about 60 miles north from Seattle, killed four people on Saturday.
The Seattle Times reports that rescue teams are still searching and it describes a harrowing scene:
" 'We have people who are yelling for help and we are out there,' Travis Hots, Snohomish County district fire chief, said about 10:30 p.m. 'This is a massive slide, and we are in a very, very fluid and unstable situation ... This is still a rescue mission.'
"With three people known dead, at least six homes destroyed and a state highway severed by the mudslide, officials advised people downstream of the area to evacuate, fearing that further damage could occur.
"Riverside residents between the slide area and Arlington, 15 miles to the west, were advised to leave their homes for the night, because of the danger that the North Fork of the Stillaguamish River could burst through the blockage created by the slide and cause immediate, severe flooding."
On Sunday morning, officials told KING-TV that 18 people remained unaccounted for, but they said the number is "fluid."
The Seattle Times quotes Travis Hots, chief of Snohomish County Fire districts 21 and 22, as saying by the time rescuers negotiated the shifting mud and got to the area where they heard screaming, "the voices had gone quiet."
Washington Gov. Jay Inslee said during a press conference that the devastation was "unrelenting and awesome." He said seven people have been rescued so far and the rescue operation is ongoing.
"Today, Oso is the heart of the state of Washington," Inslee said.
The AP reports that the slide was 135 feet wide and 180 feet deep and completely covered a part of State Route 530.
The Herald of Everett talked to a man who driving on that highway when the mudslide happened.
"I was three cars back, and I saw a truck with a boat," Paulo Falcao de Oliveira told the paper. "After that, I just saw the darkness coming across the road. Everything was gone in three seconds."
He said he heard a woman and a baby screaming. The paper adds:
"De Oliveira saw emergency crews pull a baby from the mud and debris. Police say a 6-month-old was flown to Harborview Medical Center, where the child was listed in critical condition.
"De Oliveira had been running late, and was stuck behind a slow driving vehicle.
"'I had a car that was driving in front of me that was going so slow,' he said. Had he been a few seconds faster, that would have been him in the slide. 'I feel lucky,' he said."