Overview
Early Sunday morning, September 11, 2005, three people were killed when their vehicle was caught in a sudden rock slide on westbound I-90, several miles west of the Snoqualmie Pass summit.
In the late afternoon of the next day, a boulder estimated to weigh 10 tons, broke loose, skidded down and bounced onto the shoulder of I-90 in the same vicinity. Fortunately, no traffic incident resulted from this second slide.
WSDOT hired Scarsella Brothers of Seattle to perform the emergency work to secure the rock slide area. Rock scalers pryed off loose material above the slide and 150 yards on either side of the slide. Bolts were inserted to secure the remaining rock face, and grouted into place. More than 500 cubic yards of granite that fell onto the I-90 lanes and shoulders were removed.
 | Improves Safety
By stabilizing the rockslide area, WSDOT hopes to reduce the potential of sudden slope failures in the future.
|
Partnerships & Cooperation
WSDOT worked with tribal officials to identify and minimize adverse impacts to areas of cultural, archeological or anthropological significance. When applicable, we addressed the concerns of the tribal nations using the process outlined in Section 106 of The National Historic Preservation Act and the WSDOT Tribal Consultation Policy adopted in 2003 by the Transportation Commission as part of the WSDOT Centennial Accord Plan. This project did not impact tribal resources.
Funding
WSDOT receives a set amount of funding each year to repair unstable slope areas. WSDOT also uses a statewide unstable slope prioritization process to identify and rate potential slide areas. The higher the slope rating, the higher the risk of a slide. This particular section along I-90 had a low “slope rating”, and was not high enough on the statewide list to receive funding.
This project was funded as an emergency repair project. The cost of the rock slope repair project was just over $1 million.
Contact Us
Project Engineer, Will Smith
WSDOT South Central Region Project Office
PO Box 12560
Yakima, WA 98909
Phone: 509.577.1844
E-mail:SmithW@wsdot.wa.gov
back to top