Last Updated Mar 24, 2014 10:45 PM EDT
Authorities have received 176 reports of individuals who have not been accounted for in the aftermath of the disaster that wiped out an entire neighborhood about 55 miles north of Seattle, said John Pennington, Snohomish County Emergency Management director.
"Most of us in these communities believe that we will not find any individuals alive," a somber Pennington told reporters Monday evening.
"I am a man of faith," he said, adding that people have been known to survive for days under rubble left by earthquakes and other disasters. But he said searchers believed they were "moving toward a recovery operation."
Pennington stressed that crews were not giving up, and he said 50 National Guard troops were being sent to help in the search, which includes dogs, helicopters, and heavy earth-moving equipment.
In a race to find loved ones, family members and neighbors used chain saws and their bare hands to pick through wreckage that was tangled by the mud into piles of filthy debris.
"Until that point that we feel we need to stop, we are going to keep going," Pennington said.Authorities said earlier Monday that they were looking for 108 people who had not been heard from since a mile-wide layer of soft earth crashed onto a cluster of homes at the bottom of a river valley on Saturday morning.
Pennington said Monday evening that the number of reports of people who were not accounted for had jumped to 176, but he stressed that was not likely to be a final toll. Many of those reports may be duplicates, and as authorities learned more about the area, they would be able to rule out some people who only had summer homes there, for instance, and would not have been in the disaster area.
Pennington urged the public to call authorities or to email firstname.lastname@example.org with the full names, photos, and descriptions of physical characteristics of anyone who is not accounted for.
Because the mudslide occurred on a Saturday morning, many people were still at home and there were also contractors coming to work.
"It hit at probably just the wrong time," Pennington said.
About 30 houses were destroyed, and the debris blocked a mile-long stretch of state highway. Of the 49 structures in the neighborhood, authorities have determined that at least 25 were full-time residences and 10 were part-time or vacation homes.
The search crews are finding their work both extremely difficult and time-consuming, said Snohomish County Fire District 21 Chief Travis Hots.
"Crews out there are up against enormous challenges. It's muddy, in areas it's like quicksand," he told reporters Monday.
He said the mud and debris were combined with gasoline, oil, fuel from propane tanks and waste from septic systems. "Sometime it takes five minutes to walk 40 or 50 feet," Hots said.
The rescue work was taking an emotional toll on officials and rescue workers in the close-knit community.
Retired firefighter Gail Moffett, who lives in nearby Oso, said she knows about 25 people who are missing, including entire families with young children.
"It's safe to say I'll know everyone affected or who they are," Moffett said. "There's so much pain going on in the community right now."
Elaine Young and her neighbors uncovered several bodies Sunday and had to contact authorities to get them removed.
They also found a chocolate Labrador named Buddy alive, and helped pull the dog from the rubble, leading her to wonder if other survivors could be out there, desperate for help.
"If we found a dog alive yesterday afternoon that we cut out of a part of a house, doesn't that seem that maybe somebody could be stuck up under part of a house and be alive too?" asked Young, whose home survived the slide but was on the edge of the devastation.
Authorities believe Saturday's slide was caused by recent heavy rains that made the terrain unstable.
From the beginning, rescue crews on the ground have faced dangerous and unpredictable conditions as they navigated quicksand-like mud and debris that was 15 feet deep in some places. Some who went in got caught up to their armpits in the thick, sticky sludge.
The threat of potential flash floods or another landslide also loomed over rescuers. On Monday, some crews had to pull back because of concern that a hillside could shift, but authorities said Monday evening that the crews returned after being reassured it was safe.The slide blocked the North Fork of the Stillaguamish River, which is continuing to back up, officials said. Authorities said Monday at least seven homes are now flooded, and more flooding is expected.
Frequent, heavy rain and steep geography make the area prone to landslides. Less than a decade ago, another slide hit in the same general area. Geologists and other experts said the river probably caused some erosion in the area that was carved by glaciers.
Washington Gov. Jay Inslee described the scene as "a square mile of total devastation" after flying over the disaster area Sunday. He assured families that everything was being done to find their missing loved ones.