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US 12 - White Pass - Slope Stabilization Projects

Project status

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Photo of rocks on road Rocks brought down by scaling

 Photo of scaling slopes on US 12
Scaling slope on US 12


October 2013

  • This project is complete.


When the planned projects are completed, WSDOT will have stabilized eleven slopes in a 25 mile corridor on US 12 near White Pass. The series of unstable slope projects will be on going each summer from 2006 to 2013.

View the map for project locations.

Work will consist of removing loose rock, potentially hazardous timber and other debris from the slopes. Rock anchor bolts will be used to hold large rocks on the slopes. Wire mesh slope protection fencing will be installed to protect motorists from potential rockfall onto the highway.

Why is WSDOT stabilizing these slopes?
The slopes identified on US 12 are considered high risk sites. WSDOT uses a statewide unstable slope prioritization process to identify and rate potential slide areas. We evaluate a number of factors to determine the "slope rating" of each location. The higher the slope rating, the higher the risk of a slide.

The End Result
WSDOT will evaluate the unstable slopes, remove loose rocks, timber, and debris, and stabilize the slopes using bolts and protective fencing.

Project Benefits

  • Safety. By removing unstable material and installing rock bolts and protective fencing, WSDOT will reduce the potential for future rockslides.
  • Mobility. This project will reduce the possibility of emergency closures and traffic delays due to rock slides.

What is the project timeline?
WSDOT plans to have slope stabilization construction work on US 12 through 2013.

Work on the first three sections started late summer 2006 and was completed in 2007.

Work on the second two sections (MP 162 & 162.2) was completed in 2008.

Work on the third section of slopes, west of White Pass (MP 141.8 to 142) and (MP 144.3 to 144.4), was completed in August 2009. 

Work on slopes west of White Pass (MP 142.99-143.27 & 144.13-146.90) was completed in November 2011. Work on this project was featured on a National Geographic Channel show called Rock Starts in December 2011.

Work on slopes east of White Pass near Clear Creek Falls (mileposts 154.34 to 154.38) and Rimrock Lake tunnel (mileposts 164.97 to 155.02) is schedule to be completed in the spring of 2013.

Financial Information

Funding Source Amount
Pre-Existing Funds (PEF)
Total $13.3 million 

How can I get more information?
Jeff Minnick
Project Engineer
WSDOT South Central Project Office
2809 Rudkin Rd.
Union Gap, WA 98903

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