Many survivors are only starting to feel the full impact of last weekend's mudslide ...

Many survivors are only starting to feel the full impact of last weekend's mudslide in Oso, Wash.

The search for victims entered its seventh day Friday. Ninety people are still missing, and one local official said Thursday night, 'This is going to get harder and harder.'

CBS News correspondent John Blackstone reports from just outside Oso that authorities warned of more bad news to come.

The official death toll stands at 17, but that number was likely to be raised significantly later Friday morning. As many as nine bodies found during the last few days are being cleared by the county medical examiner's office and will be added to the list.

The medical examiner's office has so far formally identified five victims: Christina Jefferds, 45, of Arlington; Stephen A. Neal, 55, of Darrington; Linda L. McPherson, 69, of Arlington; Kaylee B. Spillers, 5, of Arlington and William E. Welsh, 66, of Arlington.

The body of Jefferds' granddaughter, 4-month-old Sanoah Huestis, was found Thursday, said Dale Petersen, the girl's great-uncle.

Petersen said he arrived on the scene to help look for survivors to find that work had stopped. A firefighter informed him and others that the infant had been found, Petersen said.

He said the news provides closure for the family.

'We spent a lot of time together,' he said of the baby girl.

The first week of digging is coming to an end, but for searchers there's no end in sight, Blackstone reports.

'Trees, mud, dirt, residences, cars, some of them look like they've been put in a blender and dropped on the ground,' Snohomish County Fire Battalion Chief Steve Mason.

That's exactly the way it felt to 81-year-old Mac McPherson.

'You just kept mixing it and mixing it and mixing it, and when it got going fast enough, you took the top off and it all went voof,' he said.

Linda McPherson, his wife of 46 years, was sitting beside him when the avalanche of mud hit. He grabbed a wooden stick to dig himself out but couldn't find her.

'It's very overwhelming, and it's almost surreal,' Sue Moore, who lives in Snohomish County, told Blackstone. 'But you see the pictures, and then it starts hitting home.'

But the strength of the community is hitting home as well. Oso's determination is reflected in a new phrase: 'Oso Strong.'

Many of the searchers are local loggers who know the missing. As much as it is their mission to find bodies, each discovery is somber.

'It gets really quiet for a few minutes,' said Snohomish County Fire District 21 Chief Travis Hots. 'You can almost hear a pin drop out there. You see seasoned veterans in this business. They start to tear up. Their eyes get glossy, and it's kind of their way of paying respects to these people's loved ones.'

The possibility that dozens more people may be buried in the debris pile besides the 26 bodies already found has the potential to place Oso, with a total population of about 180, among the worst tragedies in Washington state history.

The 1980 eruption of Mount St. Helens killed 57 people and a 1910 avalanche near Stevens Pass swept away two trains and killed 96.

'We do know this could end up being the largest mass loss of Washingtonians,' Gov. Jay Inslee said Thursday. 'We're looking for miracles to occur.'

Besides the 90 missing, authorities are checking into 35 other people who may or may not have been in the area at the time of the slide. A group of people with the county emergency operations center is now making calls to eliminate that more-speculative list, said Marybeth O'Leary, a spokeswoman for the emergency operations center.

'They are names that are not complete names,' she said. 'They're things like 'I work with a guy named Bill, he didn't show up to work today.''

The governor has asked for more federal assistance, saying $4.5 million was expected to be spent on the response to the mudslide. Inslee's request was to expand Monday's federal emergency declaration that provided response teams and equipment.

Rain fell on the searchers Thursday, but the water levels on the eastern side of the slide area receded and uncovered flattened homes and crushed cars that previously had been inaccessible. An inch more was in the forecast for Friday.

Boats searched the area with dogs and crews inserted underwater cameras into vehicles to see if anybody was inside. Excavators pulled one car out of the muck, but it was unclear if they had discovered anybody inside.

The searchers walked on plywood pathways to keep from sinking into the sucking slurry. The moisture made the already treacherous surface even more unstable for workers exhausted after days of searching.

It's not only the people who are showing signs of strain.

The dogs leading searchers to possible human remains can sense stress, incident spokesman Bob Calkins said. They also can become bored by the repetition, and their handlers must take them away from the work area for a time, he said

'The real key is for the handlers to stay positive, because stress on the part of the handlers goes right down the leash to the dogs,' Calkins said.

Five people injured by the mudslide remain in a Seattle hospital, including a 5-month-old boy in critical condition.