Saturday, April 30, 2016

Rock Will Not Be Contained: Problems at the Ferguson Slide near Yosemite

The Ferguson Slide today, April 30, 2016

I thought of an Ian Malcom quote from Jurassic Park (1983) today:  "If there is one thing the history of evolution has taught us it's that life will not be contained. Life breaks free, it expands to new territories and crashes through barriers, painfully, maybe even dangerously, but, uh... well, there it is."

We were driving past the Ferguson Slide on the Merced River near Yosemite Valley, a huge slump that let loose in 2006, covering Highway 140, and forcing engineers to "temporarily" put the highway on the other side of the river. Try replacing the word "evolution" with the word "geology", and the word "life" with the word "rock", and see if this is appropriate: If there is one thing the history of geology has taught us it's that rock will not be contained. Rock breaks free, it expands to new territories and crashes through barriers, painfully, maybe even dangerously, but, uh... well, there it is.
The Ferguson Slide in November 2016. Source: http://geotripper.blogspot.com/2015/05/work-on-yosemites-ferguson-slide.html

The engineers have been intending to reopen the section of Highway 140 by constructing an avalanche shed. They began work last year by removing a huge amount of rock, and then covering the remaining slide with containment netting. Unfortunately, El Nino made its influence felt, as rainfall this year was more than average. It didn't result in disastrous flooding, but apparently excess water contributed to the failure of the slide in two separate events in November and December. The new slides destroyed half of the containment netting (yes, I'm a bit late with this news, but I haven't been up there a lot until these last few weeks). Engineers are reassessing their options, and work has stopped for the moment.


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