Wyoming, Washington State landslides: Natural or human-caused?

Landslides are a natural occurrence, but human activities can trigger them as well. Scientists are looking for causes of a landslide in Wyoming as well as one in Washington State that killed at least 39 people.

|
Matthew Brown/AP
A work crew moves a concrete barrier that failed to stop a slow-motion landslide in Jackson, Wyo., as houses and businesses in the slide zone remained at risk Sunday.

Landslides are a common occurrence, a function of geology, seismic activity, erosion caused by heavy rainfall, changes in temperature, changes in groundwater, wildfire, and other natural events

But human activities can trigger landslides as well: commercial and residential development, logging, mining, road-building, and water diversions among them.

That may have been the case in this weekend’s landslide in Jackson, Wyo., and in an earlier, massive slide in Oso, Wash., that killed at least 39 people with four more still unaccounted for.

President Obama is scheduled to visit the rural Washington State community on Tuesday. He’ll meet with victims, first responders, and recovery workers who continue to look for remains of the missing where a huge mudslide crossed the North Fork of the Stillaguamish River and roared through the town of Oso.

The Wyoming slide has been happening – so far, at least – in slow motion over the past two weeks.

It has sheared one hillside home in half, and it threatens more homes and businesses in its potential path. A road and parking lot have ruptured, and the residents of 42 houses and apartments have been ordered to evacuate.

Experts are unsure how long the hill will continue to move, although they don’t expect it to come thundering down like the mudslide in Washington.

"Is it weeks, is it longer? I really don't know," landslide specialist George Machan said at a town meeting Friday. "I think it's really unpredictable how long it might take. I don't expect it to end in a day."

Both natural and human causes may have combined to start the slide.

Authorities are looking into whether recent construction at the foot of East Gros Ventre Butte made the slope unstable. They say there could be a variety of other causes, including prior construction at the site.

The area has been graded for roads and businesses in recent years, including a new Walgreens. That could have weakened the hillside and set the stage for its collapse.

Meanwhile, warmer weather and a wet winter that put more water into the ground, likely acted as a lubricant for unstable rocks and soil, which happens throughout the Rocky Mountain region.

"As more people move into more mountainous environments, the opportunities for interactions between human infrastructure and people, and landslides, increase,” said David Montgomery, a geology professor at the University of Washington in Seattle. "When you add it up, it's actually a major geological hazard.”

Oso, Washington, in the Pacific Northwest is a rural area with a much small population than Jackson, heavily forested and with more rainfall. Residents include retirees, vacation-home owners, those who commute to nearby towns, and loggers.

Questions are being raised about logging there and how it might have contributed to the slide.

The hillside in and around the slide area, which slopes steeply down toward the river, has seen much clear-cut logging over the years.

Landslides have followed logging in that area at least four times.

"There was cutting in the 1940s; it failed in the '50s. There was cutting in 1960, then it failed in the mid-'60s. There was cutting in '88; it failed in '91. There was cutting in 2005, and it failed in 2006 and in 2014,” geomorphologist Paul Kennard told KUOW radio station in Seattle.

Media reporting since the slide on March 22 reveals that authorities knew about but failed to fully heed the warnings of scientists that such a disaster was a real threat.

Authorities considered – but then rejected – a suggestion that they buy out home and business owners whose properties lay just across the Stillaguamish River from a steep hill that had fallen away several times before. The Seattle Times newspaper reported that Snohomish County officials analyzed the situation, finding that the costs of a buyout “would be significant, but would remove the risk to human life and structures.”

Instead, they decided to build a wall intended to stabilize the slope, leaving existing structures in place and allowing more to be built.

Robin Youngblood, who was saved by helicopter after her home was destroyed, said she hopes to speak with the President when he visits Tuesday, if only to convey that laws need to change to ensure homes aren’t built in such risky areas, or that residents are warned when they are.

“People need to be given exact knowledge of whatever dangers they may be facing,” she said. “Nobody should have been living there.”

This report includes material from the Associated Press.

You've read  of  free articles. Subscribe to continue.
Real news can be honest, hopeful, credible, constructive.
What is the Monitor difference? Tackling the tough headlines – with humanity. Listening to sources – with respect. Seeing the story that others are missing by reporting what so often gets overlooked: the values that connect us. That’s Monitor reporting – news that changes how you see the world.

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.

QR Code to Wyoming, Washington State landslides: Natural or human-caused?
Read this article in
https://www.csmonitor.com/USA/2014/0420/Wyoming-Washington-State-landslides-Natural-or-human-caused
QR Code to Subscription page
Start your subscription today
https://www.csmonitor.com/subscribe