AP Photo/The Herald, Genna Martin
A fatal mudslide brought debris down the Stillaguamish River near Oso, Wash., Saturday, March 22, 2014, stopping the flow of the river and destroying several homes. (AP Photo/The Herald, Genna Martin) Genna Martin/The Herald/Associated Press
About 18 people are still unaccounted for after a massive mudslide in rural northwest Washington state killed at least three people and forced evacuations because of fears of flooding, authorities said Sunday.
The slide of mud, trees and rocks happened about 11 a.m. Saturday. Several people — including an infant — were critically injured and at least six houses were destroyed. Between 28 and 30 homes overall are believed to have been impacted.
Snohomish County Fire District 21 Chief Travis Hots said at a news briefing Sunday morning that "we suspect that people are out there, but it's far too dangerous to get responders out there on that mudflow."
Searchers in helicopters will be flying over the area of the 2.6-square-kilometre mudslide Sunday to find people who may have been able to get out on their own, as well as look for other signs of life.
Authorities are also trying to determine how to get responders on the ground safely, Hots said, describing mudflow as "like quicksand."
Officials described the deadly slide as "a big wall of mud and debris" that blocked about 1.6 kilometres of State Route 530 near the town of Oso, about 90 kilometres north of Seattle. It was reported about 18 metres deep in some areas.
Several people — including an infant — were critically injured and as many as 30 houses were destroyed. The slide wiped out one neighbourhood, where there were about 28 to 30 homes, authorities said.
Hots said the number of missing is fluid and could change because some people may have been in cars and on roads when the slide hit just before 11 a.m. Saturday.
The mud was so thick and deep that searchers turned back late Saturday after attempting to reach an area where voices were heard crying for help.
Rescuers couldn't hear any signs of life once they got closer, and the decision was made to back out due to safety reasons, Hots said.
Washington state 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 per cent aggressive rescue going on right now," said Inslee, who proclaimed a state of emergency.
4 people confirmed dead
The slide blocked the North Fork of the Stillaguamish River, which prompted an evacuation notice because water was rising rapidly behind the debris.
Authorities worried about severe downstream flooding if water suddenly broke through the debris.
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.
John Pennington, director of the 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 Snohomish County sheriff's office reported Saturday that two people had been killed at the scene. Authorities later said one of the people who was rescued died at a hospital.
On Sunday afternoon, officials confirmed another death when searchers found a body in the debris field.
Fire Chief Hots said emergency responders and technical rescue personnel found "no signs of life" as they scoured the area.
Shari Ireton, a spokeswoman for the Snohomish County sheriff's office, said Sunday a total of eight people were injured.
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.
Five of the injured were brought to Cascade Valley Hospital in Arlington, and one has already been treated and released, said hospital spokeswoman Jennifer Egger. She didn't know the condition of the others.
Bruce Blacker, who lives just west of the slide, doesn't know the whereabouts of six neighbours.
"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 neighbourhood that was destroyed, he said.
"I'm hoping for the best," Blacker said.
The American Red Cross set up at the hospital, and evacuation shelters were created at Post Middle School in Arlington and the Darrington Community Center.
Dane Williams, 30, who lives a few miles (kilometres) from the mudslide, spent Saturday night at the Red Cross shelter in Arlington.
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, just looking at them," Williams said Sunday.
'Gone in three seconds'
One eyewitness told the Daily Herald that he was driving on the roadway and had to quickly brake to avoid the mudslide.
"I just saw the darkness coming across the road. Everything was gone in three seconds," Paulo Falcao told the newspaper.
Search-and-rescue help came from around the region, plus the Washington State Patrol and the Army Corps of Engineers. More than 100 rescuers were at the scene.
The National Weather Service issued a flash flood watch for Snohomish County through Sunday afternoon.
Authorities believe the slide was caused by ground water saturation from recent heavy rainfall.
John Pennington from the Snohomish County Department of Emergency Management said the area has a history of unstable land. He said a slide also happened there in 2006.
Pennington said Saturday's slide happened without warning.
"This slide came out of nowhere," he said.
Map: Approximate slide area
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