Multiple full closures are coming to Cosi Hill for slide evaluation and drilling

The Washington State Department of Transportation are warning travelers that ongoing landslide assessment will force closures of US 101 through the Cosi Hill area.

According to a release, engineering geologists for the Washington State Department of Transportation will drill and collect samples of recent roadway settlement. 

During this work, the highway will be closed to all travelers.

The roadway has been reduced to one-way alternating traffic since Jan. 24, 2019, when the settlement was discovered. 

The full closures are needed to allow crews to safely assess the nearly 1-foot of settlement that caused cracks to develop in a portion of the roadway and recommend long-term repairs. 

During the closures, travelers will detour using State Route 107 and Blue Slough Road.

US 101 closure between milepost 80.6 and milepost 77:

  • 8 a.m. to 10 a.m. Saturday, Feb. 22
  • 8 p.m. to 10 p.m. Tuesday, Feb. 25, and Friday, Feb. 28.

Outside of these hours, traffic will resume alternating through a single lane of roadway while maintenance crews continue to monitor the site. WSDOT will announce any additional closures as they are scheduled. 

A timeline for permanent repairs will be shared once it is finalized.

This new roadway settlement is roughly 1,000 feet away from a separate slope stabilization project that began last summer.