The death toll from a massive landslide in Washington state stood at 24 on Wednesday, but the mud-stricken community braced for a higher body count as search teams combed through debris looking for scores of people still missing four days after the disaster.

Emergency management officials said as many as 176 people remained unaccounted for on Wednesday near the rural town of Oso, where a rain-soaked hillside collapsed on Saturday, cascaded over a river and engulfed dozens of homes on the opposite bank.

Meanwhile, Snohomish County officials began to address criticism for allowing new home construction on parts of the disaster site after a 2006 landslide in the same vicinity, which itself followed numerous reports detailing the risks of slides dating back to the 1950s.

A 1999 study by geologist Daniel Miller for the U.S. Army Corps of Engineers warned of the potential for a "large catastrophic failure" in the area, northeast of Seattle.

Speaking to reporters on Wednesday, the county's emergency management director, John Pennington, said local authorities had spent millions of dollars on work to reduce landslide risks in the area after the 2006 event.

He suggested that while officials and residents were aware of vulnerability to unstable hill slopes, Saturday's tragedy came out of the blue.

"We really did a great job of mitigating the potential for smaller slides to come in and impact the community," Pennington said. "So from 2006 to this point, the community did feel safe, they fully understood the risks."

But he also said: "People knew that this is a landslide-prone area. Sometimes big events just happen. Sometimes large events that nobody sees happens. And this event happened, and I want to find out why. I don't have those answers right now."

DEATH TOLL HIGHER

Pennington told a Wednesday morning news conference that he expected to have updated figures later in the day on the number of missing individuals, and presumably the death toll.

Search and rescue operations tapered off overnight but ramped up to full strength again at first light on Wednesday, using dogs to pinpoint the possible location of victims, as well as electronic equipment such as listening devices and cameras capable of probing tight voids in the debris.

"We're not backing off. We're still going at this with all eight cylinders to get everyone out there who is unaccounted for," local fire chief Travis Hots said.

The discovery of additional bodies came as crews searched in

drizzling rain for survivors amid fading hopes that anyone could still be plucked alive from the massive pile of heavy muck and debris.

Officials said they were hoping that the number of missing would decline as some of those listed turned out to have been double-counted or were slow to alert family and officials of their whereabouts. Eight people were injured.

Although authorities have said chances were low of finding more survivors in the cement-like mud blanketing the landscape, Hots said about 50 more searchers had been brought in to sift through the square-mile disaster zone in hopes of a miracle.

The slide already ranks as one of the worst in the United States and has devastated residents of the roughly square-mile area where they had their homes on the banks of a river.

In 1969, 150 people were killed in landslides and floods in Nelson County, Virginia, according to the U.S. Geological Survey.

Pennington said he expected President Barack Obama would soon issue a formal disaster declaration for landslide victims, making direct federal assistance available to survivors of the tragedy.

(Additional reporting by Bill Rigby; Writing by Eric M. Johnson in Seattle; Editing by Cynthia Johnston and Dan Grebler)