Mudslides have forced closure of Highway 20 over the Loup for the third consecutive year. Repairs continue in the milepost 222.4 area.
Washout repairs require shutdown
State Highway 20 remains closed until 9 p.m. next Tuesday (June 4) at milepost 222.4 as contractors work on emergency repairs to a washout that occurred on May 1. The closure started earlier this week on Tuesday morning (May 28). Previously, the highway had been open to one-lane, signal-controlled traffic.
“The contractor has reached a point in their work that will require them to excavate very soft fill material under the roadway, which could compromise the stability of the lane that is still open to traffic,” the Washington State Department of Transportation (WSDOT) said in a press release. “For the safety of drivers, it will be necessary to restrict all travel through that area until that work is complete.”
The closure will require traffic between the Methow Valley and Okanogan/Omak to use the 70-mile workaround that became familiar two years ago when the highway was closed for more than three months. During the current closure, westbound traffic from Okanogan toward Twisp will again be detoured south along U.S. 97 and eastbound traffic from Twisp toward Okanogan will be detoured south along state Highway 153.
Mudflows in early April of 2017 at milepost 222 undercut the road, causing extensive damage. Multiple debris slides and road failures along Highway 20 on both sides of the Loup Loup summit forced the closure of a 16-mile stretch of the highway. The road remained closed until July 10, when it opened partially with one lane through the most-damaged sections. Repairs cost more than $4 million.
In April 2018, mudslides came down over Highway 20 east of Loup Loup Pass in the same area where slides closed the highway almost exactly a year earlier, causing a brief closure.
This year’s May 1 mudslide eroded earth below the highway about 7 miles east of the summit, leaving the outer lane and guardrail suspended in the air. WSDOT has hired Hurst Construction of East Wenatchee under a $1.3 million 30-day emergency contract. WSDOT said earlier that motorists should expect a “quick fix.”
The 2017 slides were triggered by rainstorms, but WSDOT geotechnical engineers determined that this year’s slide was a result of groundwater that saturated soil below the road and caused the washout.
