The Oso Slide

Above is a recent photograph of an area in Oso, Washington.  Last month, a massive landslide of earth, loosened by a month of torrential rains, slid down the hillside and buried a street of homes at the bottom of the slope near the Stillaguamish Riveer.

Most of the reports have been of people lost and dead. The excavation will continue for a long time.  The loss of life has been great and tragic.  We need to understand what happened.

This Sunday, in the New York Times Review section, Timothy Egan discussed the slide, praising fly fishermen, Native Americans and wise biologists.  He also took a big swipe at the lumber industry, saying this:

"A federal survey determined that nearly 50 percent of the entire basin above Deer Creek had been logged over a 30-year period.  It didn't take a degree in forestry to see how one event led to the other (the slide)."

In one sense, Egan is right.  It didn't take a degree in forestry.  What it took was some understanding of geology.

Big slides on the same hillside were recorded in 1949, 1951, 1967, 1988 and 2006.  The slides started before the logging Egan deplores, most likely hundreds of years before anyone besides Native Americans arrived in the area.

The slide in January 2006 re-arranged the course of the Stillaguamish River, and not for the first time.  There were reports of "the eerie sound of trees constantly snapping as the river pushed them over."  Meanwhile, work continued on five new homes on Steelhead Drive, which now is buried in mud.  Another home was added in 2009, and a new double-wide mobile home was located on the street in 2013. One question that deserves an answer is why Snohomish County didn't act long ago to stop development on Steelhead Drive.

The dangers had been reported.  Warnings came in a 1997 watershed analysis by the State of Washington that apparently never was implemented.  In a 1999 report by the Army Corps of Engineers.  In a 2010 report by the Snohomish County Department of Emergency Management.

Take a look at the slide area at the base of mountain below.  What you see are many large trees uprooted and carried down the hill.  In fact, the heavy rains in March seem to have saturated the ground to a level below tree roots.  That the slide washed so many trees down the slope suggests that tree roots were not enough to hold the land in place.

I was raised in the Pacific Northwest, and I actually know a few foresters.  I talked with a couple of them yesterday.

They reminded me of a few facts.  First, when forest areas are clearcut, the tree roots remain and decompose over a period of years, slowly releasing their hold on the land beneath.  Meantime, forests are replanted (as required by law) and grow to replace the trees that were cut.  If Egan had gone back last month to the clearcut area he observed 25 years ago, he would have found substantial stands of large trees.

"Look at the photos from the slide in Washington," one forester told me.  "There are trees, big ones, at the top of the area.  The idea that this was caused by over logging, especially 25 years ago, is b------t."

Back to Mr. Egan. "Yes, but who wants to listen to warnings by pesky scientists, to pay heed to predictions by environmental nags, or allow an intrusive government to limit private property rights?  That's how these issues get cast.  And that's why reports like the ones done on the Stillaguamish get shelved.  The people living near Oso said no one ever informed them of the past predictions (of hillside slides)."

It seems to me that the "pesky scientists" who were ignored were the geologists who warned repeatedly that the hillside was unstable and that mud slides, including big ones, were inevitable.

As for the environmentalists, whom Egan imagines are regarded by loggers as "environmental nags," they also seemed to be concerned about the hillside.

"I don't think that the fact that the slide happened surprised anyone who has looked at this area before," said a conservation expert at Oregon Wild, a nonprofit group.  "It wasn't really a matter of if, but when."

There's a lot of snark in Egan's article and disdain for people asserting property rights.  He resents that the company that owned the land at the top of the hillside pushed hard to log it.  And it appears there may have been an extra acre logged on top of the hillside.  In fact, the logging took place in what has been described as a pie-shaped slice, with the narrow tip near the crest of the hillside.  The slide originated from a much broader area.

It's unfortunate the New York Times couldn't find a commenter who was less absorbed with righteous certainty and better acquainted with the facts on the ground in Oso.