SR 530 closed indefinitely after Snohomish County landslide

After the tragic landslide along SR 530 in the town of Oso on Saturday morning, search and rescue operations are underway for many unaccounted people in Snohomish County. SR 530 between Whitman Road (milepost 36) and 310th Street Northeast (milepost 39) is closed indefinitely. It’s likely a long-term closure.

A hillside gave way about five miles east of Oso, and north of SR 530 across the north fork of the Stillaguamish River. The affected area is about a mile wide and estimated to be up to 35 feet deep in places. The headscarp, the location on the hill where the slide began, is about 1,500 feet wide and 600 feet tall.

We are working closely with Snohomish County, Washington State Patrol and a number of other state and local partners in the emergency response.

Right now, it’s not safe for crews to go into the slide area. Silt is still moving from hillside, which is potentially hazardous to crews below. We’re helping clear some mud from the road to blaze a trail for rescue workers, but it’s too soon to tell how much damage has been done to the highway.

At the moment, geologists from several agencies including WSDOT are on-scene and monitoring the hillside for the safety personnel watching for further safety issues.

There are no good detour options around the portion of SR 530 affected by the mudslide. Those heading to and from Darrington need to use SR 530 to SR 20, and then take I-5. The detour is about an hour.

We also teaming up with Snohomish County to clear snow from Mountain Loop Highway. It’s a seasonal auxiliary road owned by the county and Forest Service that usually is closed in the winter. Once opened, the 25 mph gravel road will serve as an emergency route to and from Darrington. Crews working on the clearing effort reached the summit of Mountain Loop Highway around 11:30 a.m. today. Previous reopening estimates indicated the highway would open Thursday. There is potential that the work will be completed earlier than planned.

Currently, we are reaching out to potential contractors so we can start cleanup efforts as soon as possible. Governor Inslee declared a state of emergency late Saturday night so that we can apply for federal relief funds to cover the cleanup costs for reopening SR 530.The current slide is unrelated to previous work on the south side of the highway at Skaglund Hill. Between 2006 and 2012, our contractor crews installed a rock buttress along the south bank of the Stillaguamish River just below SR 530. This reinforced and stabilized the hillside. We also installed a series of drainage pipes into the hillside and a rock wall that cost $13.3 million.

Snohomish County has asked that all survivors of the slide or people missing someone call (425) 388-5088.
For up to the minute information from the Emergency Operations Center, check Snohomish County’s Twitter feed and Facebook page.