Rebuilding SR 530 - Completed September 2014

On Saturday, March 22, 2014, a massive landslide struck the town of Oso in North Snohomish County, bringing down 10 million cubic yards of mud and debris and blocking and damaging SR 530 and blocking the north fork of the Stillaguamish River. The slide blocked both directions of the highway from Whitman Road to 310th Street Northeast, covering about three miles, and cut off access between Arlington and Darrington.

While an emergency search and rescue operation was deployed, WSDOT carefully worked out a plan to restore traffic and rebuild the highway when clearance was given.


Working with the community to rebuild SR 530
Over six months, WSDOT and three contractors - IMCO Construction, Granite Construction and Atkinson Construction - worked closely and respectfully with the local communities to reestablish a direct traffic route between Darrington and Arlington/I-5 and to rebuild SR 530:

  • Opening an access road: On April 29, 2014, WSDOT and Granite Construction worked with Seattle City Light to open an access road to traffic. This provided a more direct route between Arlington and Darrington than the original lengthy detour to SR 20. Granite provided pilot cars to lead vehicles one direction at a time over the unpaved road, with typical trips lasting about 10 minutes.
  • Clearing and repairing the existing SR 530: IMCO Construction crews carefully worked to clear debris from SR 530, working slowly and respectfully to ensure that as many personal belongings as possible were retrieved. IMCO then repaired, repaved and restriped the existing SR 530 roadway and on Sunday, May 31, the highway opened to two-way traffic led by a pilot car. This provided access on a paved roadway to traffic between Darrington and Arlington.
  • Constructing an east section of SR 530: Contractors from Atkinson Construction built a new east section of SR 530 adjacent to the east section of the existing roadway. Two culverts were also constructed.
  • Constructing a west section of SR 530: Contractors from Atkinson Construction built a new west section of SR 530 through the slide area and adjacent to the west end of the existing roadway. The new SR 530 was elevated due to the risk resulting from the landslide and the geographic changes to the North Fork Stillaguamish River.
  • Opening the highway: The new SR 530 was reopened ahead of schedule, on the evening of Monday, Sept. 22, 2014.
  • Landscaping, stream restoration and roadway demolition: Contractors removed the pavement of the existing roadway and installed landscaping and scour protection rock.


Partnerships & Community Engagement
Throughout the process, WSDOT coordinated  closely with private and public groups and agencies as well as elected leaders, including: The Office of the Governor, U.S. Senators and Representatives, state legislators, the city of Arlington, the town of Darrington, the town of Oso, Snohomish County, Department of Fish and Wildlife, Department of Ecology, Department of Natural Resources, Seattle City Light, Snohomish County Regional Transportation Planning Organization, Community Transit, Washington State Trucking Association, Darrington Chamber of Commerce, Arlington-Smokey Point Chamber of Commerce.


  • The SR 530 reconstruction project is funded with $28.1 million of Federal Emergency Relief funding.


How can I get more information?

Harmony Haveman Weinberg
WSDOT Communications
Phone: (206) 440-4475