ARLINGTON, Wash. (AP) — Looking for signs of life in the quicksand-like mud below, searchers in helicopters scanned a huge debris field Sunday trying to find 18 people still unaccounted for following a landslide that killed at least three people and destroyed a small riverside neighborhood in rural Washington state.
As crews took to the sky above the 1-square-mile mudslide that left several people — including an infant — critically injured and displaced 20 to 30 more, concerns remained about a blocked river in the area that threatened to flood homes.
Rescuers' hopes of finding more survivors were buoyed late Saturday when they heard people yelling for help from within the debris field, but they were unable to reach anyone. The mud that destroyed as many as 30 homes was so thick and deep that searchers had to turn back.
Rescuers heard nothing when they got closer, and the decision was made to retreat because it was too dangerous, Snohomish County Fire District 21 Chief Travis Hots said Sunday.
"We have this huge square-mile mudflow that's basically like quicksand, it's extremely fluid," he said.
The slide wiped through what neighbors described as a former fishing village of small homes — some nearly 100 years old. The neighborhood "is not there anymore," Hots said.
Because of the unstable situation, authorities said it was too dangerous to send rescuers on foot into the area Sunday.
Some of the missing may have been able to get out on their own, authorities said. The number unaccounted for could change because some people may have been in cars and on roads when the slide hit just before 11 a.m. Saturday, Hots said.
Officials described the mudslide as "a big wall of mud and debris." It blocked about a mile of State Route 530 near the town of Oso, about 55 miles north of Seattle. It was reported about 60 feet deep in some areas.
Authorities believe the slide was caused by ground made unstable by recent heavy rainfall.
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.
"There is a full scale, 100 percent aggressive rescue going on right now," said Inslee, who proclaimed a state of emergency.
The slide blocked the North Fork of the Stillaguamish River. With the water rising rapidly behind the debris, authorities worried about downstream flooding and issued an evacuation notice Saturday. The water had begun to seep through the blockage Sunday afternoon.
Snohomish County officials said Sunday that residents could return home during daylight hours, but that they'll likely re-issue the evacuation order Sunday night. Even though the evacuation had been lifted, Inslee urged residents to remain alert.
John Pennington, director of Snohomish County Emergency Management Department, said there were concerns that the water could break downstream, as well as back up and flood areas upstream.
The National Weather Service issued a flash flood watch for Snohomish County through Monday afternoon.
Shari Ireton, a spokeswoman for the Snohomish County sheriff's office, said Sunday that a total of eight people were injured in the slide.
A 6-month-old boy and an 81-year-old man remained in critical condition Sunday morning at Harborview Medical Center in Seattle. Hospital spokeswoman Susan Gregg said two men, ages 37 and 58, were in serious condition, while a 25-year-old woman was upgraded to satisfactory condition.
Bruce Blacker, who lives just west of the slide, doesn't know the whereabouts of six neighbors.
"It's a very close knit community," Blacker said as he waited at an Arlington roadblock before troopers let him through. There were almost 20 homes in the neighborhood that was destroyed, he said.
Search-and-rescue help came from around the region, including the Washington State Patrol and the Army Corps of Engineers. More than 100 were at the scene.
Evacuation shelters were created at Post Middle School in Arlington and the Darrington Community Center.
Dane Williams, 30, who lives a few miles from the mudslide, spent Saturday night at a Red Cross shelter at the Arlington school.
He said he saw a few "pretty distraught" people at the shelter who didn't know the fate of loved ones who live in the stricken area.
"It makes me want to cry," Williams said Sunday.
Associated Press writer Phuong Le in Seattle contributed to this report.