OLYMPIA, Wash. — Eight people were dead and at least 18 were still missing nearly two days after a landslide in Washington state buried homes and cars under mud and tangled debris up to 15 feet deep, authorities said.

The search for victims was due to resume early on Monday after dangerous, quicksand conditions forced rescue workers to suspend their efforts at dusk on Sunday. Some workers had to be dragged to safety after becoming mired in mud to their armpits.

The landslide was triggered after rain-soaked embankments along State Route 530 near Oso, Washington, about 55 miles northeast of Seattle, gave way on Saturday morning, washing away at least six homes.

A spokesman for the Snohomish County Sheriff’s Office said eight bodies had been found in the square mile of tangled debris, rocks, trees and mud by Sunday evening. A further eight people were hurt in the landslide.

“We didn’t find anybody alive. There was no sign of life” after a search of much of the area on foot, Snohomish County Fire District 21 Chief Travis Hots told a news conference on Sunday, adding that the tally of missing was likely to grow.

A press briefing was slated for 9 a.m. PDT on Monday.

“I have a sense that we’re going to have some hard news here,” Washington Governor Jay Inslee said after flying over the affected area on Sunday.

The slide in the foothills of the Cascade Mountains along the Stillaguamish River piled mud, rock and debris up to 15 feet deep in some places.

It blocked the flow of the river, creating floods and a backup of water behind a natural dam of mud and debris, but the threat to people downriver had begun to ease, Inslee said.

The highway was closed in both directions, with no timeline for it to be reopened, he said.

The Snohomish County sheriff’s office has asked people affected by the slide to report to the Red Cross so an accurate count can be made of the missing.

Washington state Lieutenant Governor Brad Owen has declared a state of emergency in Snohomish County.