By Victoria Cavaliere
SEATTLE (Reuters) - A rain-soaked hillside that collapsed in Washington state last March, killing 43 people, was so saturated it continued to slough huge pieces of mud more than 10 minutes after it gave way, a newly released video showed on Monday.
The three-minute cell-phone video shows large waves of mud and debris streak down the hillside on the north fork of the Stillaguamish River in the immediate aftermath of the massive landslide that crashed onto homes in the foothills of the Cascade Mountains.
"The mountain's still coming down. This is crazy," a woman's voice can be heard saying on the video, filmed by a resident and posted on YouTube by the Everett Herald newspaper.
Elizabeth Honnerlaw, who shot the video, had been driving in the area with daughter Jaclyn when they paused to capture the unfolding disaster near the community of Oso, about 55 miles northeast of Seattle.
“When we went into the field, we could still see some of the mountain coming down,” Jaclyn Honnerlaw told the newspaper.
Joe Smiley, a spokesman with the Washington State Department of Natural Resources, said scientists who had viewed the video online said it reinforced the view that the soil had become very liquefied, noting it showed earth still giving way more than 10 minutes after the original collapse.
"With the geologists, one thing they noticed was how dark the soil looked and saying that shows how saturated it was. And that might be from an old lake bed up there," he said.
Geologists are still examining how unstable the hillside had become and what factors led to the loss of its solid state under a process called liquefaction.
Department of Natural Resources geologists said the video appeared to support a theory that the runout might have become so powerful and destructive because the sediment was perched on a clay-rich ancient lake bed.
The sunny-day slide followed one of the wettest winters on record for the region, scientists said. It destroyed part of a state highway and swallowed about three dozen homes, killing 43 people.
The area was known to be at risk for landslides. In 1999, the U.S. Army Corps of Engineers said the hillside posed a "potential for a large catastrophic failure." Residents have accused state and local officials of not doing enough to warn them of how dangerous the slide could be.
(This story has been refiled to add missing apostrophe in headline)
(Reporting by Victoria Cavaliere; Editing by Cynthia Johnston and Mohammad Zargham)