OKANOGAN - Repairs are scheduled to begin soon on the washout of Highway 20 near Rock Creek west of town.
Wide load restrictions and single-lane, portable signal traffic control remain in place.
A portion of the highway washed out May 1.
An emergency contractor, Hurst Construction of East Wenatchee, has been named to rebuild the hillside under the eastbound lane of Highway 20 between Little Loup Creek and Rock Creek.
State Department of Transportation geotechnical engineers studied the site for several days and designed a repair plan that could exceed $1 million.
Department spokesman Jeff Adamson said Hurst will start immediately to get necessary insurance, bonding and permits, and planned to begin staging equipment at the site as early as last weekend.
For now, as the hillside under the westbound lane remains stable and single-lane, alternating traffic will continue, as will oversize load restrictions. No vehicles wider than 12 feet are being permitted.
As the repair work proceeds, some full closures and a detour are likely to be necessary, Adamson said.
An estimated 15,000 to 20,000 cubic yards of rocks and mud slid toward Loup Loup Creek hundreds of feet below the highway.
“Our geotechnical engineers determined ground water saturated the soils and caused the washout below the road seven miles east of Loup Loup Pass at milepost 222.4,” he said.
There is no estimate for how long the repairs will take. The initial hurdle to overcome is locating and transporting 2,000 dump truck loads of boulders, rock and gravel to rebuild the hillside.
The current slide area is about a mile east from where a series of slides closed 16 miles of the highway from April to July 2017.