As many as 176 people were reported missing in the massive landslide, and local emergency management officials expressed doubt anyone else would be plucked alive from the muck that engulfed dozens of homes when a rain-soaked hillside near Oso, Washington, collapsed on Saturday morning.
Meanwhile, concern lingered about flooding from water backing up behind a crude dam of mud and rubble dumped into the North Fork of the Stillaguamish River by the slide in an area along State Route 530, about 55 miles (90 km) northeast of Seattle.
"The situation is very grim," said Travis Hots, the local fire chief. "We're still holding out hope that we're going to be able to find people that may still be alive. But keep in mind we haven't found anybody alive on this pile since Saturday in the initial stages of our operation."
President Barack Obama, who was in Europe on Monday for a meeting with world leaders, signed an emergency declaration ordering U.S. government assistance to supplement state and local relief efforts in the aftermath of the mudslide and flooding, the White House said.
Several dozen homes were believed to have sustained some damage from the slide, John Pennington, director of the Snohomish County Department of Emergency Management, told reporters at a command post in the nearby town of Arlington.
More than 100 properties were hit by the cascading mud, 49 of which had a house, cabin or mobile home on them, Pennington said. At least 25 of those homes were believed to have been occupied year round.
"I'm pissed off I'm losing my house. I mean I hate to lose it. I've been working on it for 15 years," said 73-year-old Dennis Hargrave, who drove up from Kirkland, near Seattle, to learn what he could of his vacation home.
"But that's not my concern. My concern is, are my neighbors still alive Is anybody surviving this" he said.
Rescuers using dogs, earth-moving equipment and aircraft searched under partly cloudy skies on Monday after treacherous quicksand-like conditions forced rescue workers to suspend their efforts at dusk on Sunday. Some workers, mired in mud up to their armpits, had to be dragged to safety.
No one was pulled out alive on Monday from the disaster scene, in an operation that has been stymied by treacherous conditions, with gasoline and other contaminants strewn across the muddy debris field, Hots said.
The compressed mud filling some homes is like concrete, and it can take up to an hour to dig out four buckets of the stuff, he said.
Members of a search team were forced again to briefly retreat on Monday from the western edge of the slide area after movement was detected along a 1,500-foot (460-meter) stretch of earth, said Rebecca Hover, a spokeswoman for the county executive's office.
Authorities on Monday also reported a sharp jump in the number of people listed as unaccounted for in the chaos after the disaster, heightening fears the casualty toll could climb even higher. Eight people were injured in the landslide.
The number of people missing had been listed at 18 or more on Sunday, before jumping on Monday first to as many as 108 and then as high as 176, although Pennington said some reports were vague and could involve overlap.
The operation is moving into a recovery phase, instead of a search for survivors.
"Most of us ... believe that we will not find any individuals alive," Pennington said, although he said he did expect the number of missing to drop dramatically as those unaccounted for are tracked down and the chaos subsides.
A 22-week-old infant injured in the slide remained in critical condition on Monday at Harborview Medical Center in Seattle, after being taken there by helicopter along with his mother who also was hurt, said hospital spokesman Brian Donohue.
HOPE FOR THE MISSING
One retired lumber mill worker, Reed Miller, told Seattle television station KOMO-TV that his riverfront house was demolished by the slide, and that his 47-year-old son, with whom he shared the home, was probably swept away with it.
"Well, he was at home. As far as I know he's gone," said Miller, who was at a grocery store in town at the time. "There's no official (word) that he's been found yet, but he could be buried. I just don't know."
The potential number of victims in harm's way was higher on a Saturday, with many people at home, than on a weekday when more residents would have been at work or school, Pennington said. He said search teams were also trying to account for an unspecified number of construction workers who were in the area and motorists who were driving by at the time.
But authorities were hoping many of those reported as missing would turn out to be survivors who were either double-counted or slow in alerting loved ones and local officials as to their whereabouts.
The slide in the foothills of the Cascade Mountains along the Stillaguamish River piled mud, boulders and rubble up to 15 feet (5 meters) deep in some places. It blocked the flow of the river, backing up water behind a natural dam that caused flooding of seven homes upstream of the slide, Pennington said.
"The bad news is that the water continues to rise and homes are inundated up to the eaves in many cases," he said. "If there is a silver lining in that event ... it is that it is a slow, methodical rise. You can see the danger."
Authorities said as the volume and pressure of water behind the dam continued to build, there was a chance that additional downstream flooding and mud flows could be unleashed.