Tuesday, March 25, 2014

Did clear-cutting of forest contribute to Oso, Snohomish County, Washington mudslide?

Official: Residents knew of 'high risk' of landslides
Oso, Washington is still reeling from a mudslide that has claimed the lives of at least 14 people. There are 176 reports of people missing, though there could be duplicate names among that list.
Elizabeth Weise, Janet Kim and John Bacon
March 25, 2014

DARRINGTON, Wash. — People living in the tiny village destroyed by a mudslide knew there was a "high risk" of slides, a local official said Tuesday.

"This entire year we have pushed message after message that there's a high risk of landslides," said John Pennington, director of Snohomish County Emergency Management. "The dangers and the risks are known."

Pennington said the death toll from Saturday's tragedy remained at 14. Scores more people were reported missing, but he would not estimate how many bodies were still buried in the tons of mud and crumpled homes in Oso, about 55 miles northeast of Seattle.

Pennington acknowledged that the chance of finding survivors was small, but said the effort remained a rescue and recovery operation.

"I've said it before — I believe in miracles," he said. "I believe that people can survive these events."

The collapse followed weeks of heavy rain. Still, Pennington had previously described the disaster as "completely unforeseen." The Seattle Times, however, reported this week that multiple geological reports had warned that the area was at risk.

"No language seems more prescient than what appears in a 1999 report filed with the U.S. Army Corps of Engineers, warning of 'the potential for a large catastrophic failure,'" the Times reported.

Pennington said work had been done to mitigate slide risk since a much smaller slide struck the area in 2006

"If I'd had any idea that this was going to break that Saturday morning. ... Come on guys, we're very liberal at using reverse 911," he said Tuesday. "There's a reason that we have a very high success rate of mitigating disasters in our county. This is just one that hit us."

Pennington added that a small earthquake, measuring magnitude-1.1, had apparently struck behind the slide area on March 10.

Some people who lived in the area said flooding, not landslides, had been their primary concern.

"I wouldn't buy a house on the river myself, because rivers are unpredictable," said Marshia Armstrong, who lives in nearby Arlington. "Nobody could have predicted that whole huge slide. Another small slide, maybe, but nobody would have predicted that kind of movement."

Armstrong, a real estate agent, said one thing the media have been reporting on was the presence of "pistol butt" trees on the bluff. Those are trees under which the ground has shifted, so their trunks grow out and then up, bending like the butt of a pistol.

But in the rainy, wet Northwest "there are lots of places where the trees are growing up sideways," said Armstrong. The bluff that failed was "on the other side of the river from the houses, so they didn't think it was going to fall on their houses. They didn't think it was going to fill up the whole valley."

President Obama signed an emergency declaration ordering federal aid to the area. "I would just ask all Americans to send their thoughts and prayers to Washington state," Obama said, speaking from the Nuclear Security Summit at The Hague, Netherlands.

The landslide, which consumed a community of almost 50 homes, covers a 1-square-mile area. Darrington Mayor Dan Rankin thanked people for the outpouring of support Tuesday, adding that no additional volunteer help was needed. Federal, state and local responders were at the scene...

Hopes of finding survivors were dim, however, as the rain and muddy, unstable terrain continued to slow rescue and recovery efforts.

Weather Channel meteorologist Jonathan Erdman said more than two inches of rain may fall over the next seven days from four separate weather systems.

"Our crews are up against an enormous challenge. It's like quicksand out there," Snohomish County Fire District 21 Chief Travis Hots said.

Crews have to move extremely carefully as they work. "Some of my guys could only go 50 feet in five minutes," he said, because of the debris and danger of being sucked into the mud.

Hots said earth-moving equipment and "lots of people with local knowledge of that specific area" were providing valuable assistance in determining the most likely areas where people could be trapped.

Part of the hill had been logged in the 1980s, said University of Washington professor David Montgomery in Seattle. He studies geomorphology, how landscapes change through time.

"There's no way to know if that contributed to the slide," said Montgomery. "The surface of the Earth is constantly changing. We humans just don't always notice it, because it happens slowly. There had been landslides in that area going back hundreds of years, you can see it in the geography."

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