Officials working at the Washington mudslide said Monday evening they had identified 22 people who remained missing or unaccounted for.
Thirty people had previously been listed as missing — and that number had been in the hundreds in the days immediately after the deadly landslide near the small community of Oso on March 22.
Twenty-four bodies have been recovered as of Monday evening, and 18 of those have been positively identified, said Gary Haakenson, Snohomish County's executive director for public safety.
Haakenson stressed that the six unidentified bodies could be people who are on the list of the missing (PDF), which authorities released publicly in the hope that some of them are alive and will step forward.
Haakenson said authorities waited to release the identity of the missing because "to have released a list earlier of 90 to 100 names would have been irresponsible."
Kerrie Stevens, director of Monday's search operations, said that while "one bright spot is the weather has improved," access to the scene remained difficult "due to mud and debris being 70 feet deep" over an area of 640 acres.
Much of the muck could be toxic because the debris includes household chemicals and flammable gases from wrecked homes.
"Searching through the debris is a very laborious task," she said. "We have heavy equipment, and we have to respect the people that we are looking for."
While some volunteers have left, more than 100 remained on the scene, Stevens said, in addition to more than 80 National Guard members and nine canine teams.
Veterinarians were keeping close watch over the dogs, some of which have fallen victim to hypothermia.
"Those dogs, just like people, are getting tired and exhausted," Stevens said. "We have to rotate them in and out so they are not over-desensitized to what they are searching for."
John Cheang of NBC News contributed to this report.