Oso Slide Detour Update, Arlington WA

When searching for Arlington Real Estate, some of the properties are located East of the Oso Slide.

This is an update for the Oso Slide Detour from Washington State Department of Transportation.Oso detour

Coming up next week: Contractor crews will once again detour traffic to the Seattle City Light access road around the clock 9 p.m. Tuesday, Aug. 26 to 4 a.m. Thurs., August 28.

At all other times during the week, SR 530 will remain open to two-way traffic. Please continue to plan for up to 10 minute delays from 6 a.m. to 6 p.m. to allow safe movement of construction vehicles and equipment.


What happened during the first detour?

Many thanks to everyone for your patience during our first 31-hour detour. We’re especially sorry for any inconveniences caused by the Wednesday morning pilot car schedule.

To be sensitive to driver complaints about pilot car wait times overnight Tuesday, our contractor worked to cycle vehicles back and forth four times an hour, rather than two. This approach became unsustainable when traffic volumes increased in the early morning hours, so they returned to the regular schedule. We’re doing our best to minimize our impacts on travelers, and we appreciate your understanding as we locked in the best approach.

During this detour, contractor crews were able to complete critical work, including paving, restriping and guardrail work on the east side of the roadway. This new section is now open to traffic.

What’s coming up next?

During next week’s detour, crews will install drainage features and temporary fish passages, begin to remove the existing SR 530 roadway and restore streams on the east side of the project, and continuing work to rebuild the elevated west side of the new roadway.

Crews do not plan to work during Labor Day weekend, Aug. 30 to Sept. 1. The remaining section of new roadway is still on track to open by October.

Next planned detours:

  • 9 p.m. Tuesday, Sept. 2 to 4 a.m. Thursday, Sept. 4 (Tentative – We’ve heard your concerns about this detour occurring on the first day of school for Darrington and Arlington students, and we’re working on potential alternatives.)
  • 9 p.m. Saturday, Sept. 6 to 4 a.m. Monday, Sept. 8 (tentative)
  • 9 p.m. Tuesday, Sept. 9 to 4 a.m. Thursday, Sept. 11

Please note: Detour schedules may be cancelled or revised because of weather and construction schedule changes.

How to use the access road

Traffic on the Seattle City Light road will operate on a one-way, piloted basis around the clock. Pilot cars will escort drivers westbound at the top of each hour and eastbound on the half hour.

  • The speed limit is 10 mph, and stops along the road are not permitted.
  • Logging trucks are permitted around the clock
  • Vehicles over 105,500 pounds are not permitted.
  • Trailers up to 24 feet, including horse trailers, and dump pup trucks are allowed.
  • RVs and school buses are allowed.
  • Semi-trucks up to WB 40 are allowed.
  • Drivers should be able to negotiate their vehicles over steep grades of up to 18%.
  • Drivers are encouraged to arrive early.
  • Local access will be provided to residents within the work zone.

The best ways to get the most up-to-date detour information:

If you have any questions, please contact us at SR530info@wsdot.wa.gov.