A debris-laden landslide has closed SR 706, the popular road from Ashford, Washington to Mt. Ranier National Park. The road was first closed on February 6 as portions of the highway were covered with debris up to 6 feet thick, even re-routing streams over portions of the highway. The road will remain closed indefinitely because geotechnical engineers are concerned about the stability of the saturated slopes above the highway and about what to do with the new waterways flowing over the highway. More info can be found on the WSDOT blog.
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Devil’s Slide Tunnel Update and First Attempts to Tame the Landslide
The Devil’s Slide Tunnel project is on schedule and on budget according to a news story at ABC7News.com from earlier in June. The video (shown after the break) has a few nice shots showing rock bolting, soil nailing at the portals, and the geologic mapping and laser scanning that happens at the tunnel face.
I also came across a very neat article about how the Ocean Shore Railroad Company was the first to try to cut into the slope along what is now PCH 1 at the Devil’s Slide back in the early 1900s. They were trying to connect the then rural farming community of Half-Moon Bay with San Francisco. The railroad fought the reoccurring landslide and serious rockfalls. Ocean Shore Railroad went bankrupt in 1922 and pulled up its rails, making room for the current highway. (Photo at left from halfmoonbaymemories.com)