Groundwater saturation tied to heavy rainfall in the area over the previous month caused a landslide in Oso, Wash., on March 22.
Forty-one people are confirmed dead.
The victims range in age from 4 months to 71 years old.
On March 29, residents and rescuers paused in the rain at 10:37 a.m., the exact time when a landslide forever changed their world a week earlier. Officials eulogized the rural residents who lost their lives inside their homes or on the road when the hillside collapsed, after a month of ground-soaking rain, and obliterated everything in its path. "Our community is changed forevermore," Darrington Mayor Dan Rankin told 40 people outside the fire station, where the flag fluttered at half-staff. "It's going to take a long time to heal."
The landslide covered about a square mile and was caused by groundwater saturation tied to heavy rain in the area over the past month. It affected Oso, with a population of about 180, and Darrington, a town of about 1,350.
Rescuers have been picking through the debris carefully, not sure when or where they could find a body trapped in the mud.
Dave Norman, a Washington state geologist, said the landslide was about 4,400 feet wide with a wide debris field. In some places, the debris is 30-40 feet thick.
At least six houses were destroyed in the landslide, and as many as 16 were damaged, the Snohomish County Sheriff's Office said.
Rescuers dug desperately through the rubble left behind in the town of Oso.
The landslide cut off another town and prompted an evacuation notice for fear of a potentially "catastrophic flood event," authorities said.
The landslide, which hit an area north of Seattle, encompassed about one square mile.
The mud flow is like quicksand, according to Snohomish County Fire District 21 Chief Travis Hots.
On the Saturday the landslide hit, rescuers dug through the rubble while survivors were crying for help underneath the debris. Rescuers heard voices around 11:30 p.m. and considered trying to reach the possible survivor or survivors, but "the mud was too thick and deep," Hots told reporters, and rescuers had to back off.
In the days after the landslide, helicopters surveyed the area so that an assessment could be made as to when and how it would be safe for responders to attempt to help people.
Washington Gov. Jay Inslee toured the area by helicopter the day after the landslide.
Inslee said the conditions searchers face are extremely difficult. Sometimes it takes five minutes just to go 50 feet, he said.
Inslee said he plans to talk with federal officials about Federal Emergency Management Agency relief, adding that he'd never before seen firsthand the kind of devastation he witnessed by surveying the area by helicopter.
There is concern about whether the already struggling town can bounce back. It still hasn't recovered from the hit the logging and timber industries took in the 1970s, when so many people lost their jobs. The main artery that connected Darrington to the outside world -- State Highway 530 -- has been severely damaged by the landslide, and the state transportation department is now mulling whether it can ever be reopened.