Loup Loup Land Slides


Heavy rains started in the beginning of April 2017.

Roadways, both asphalth and dirt roadways, started to sluff off.

On April 15, 2017 WEDOT advised that State Route 20 (Loup Loup Pass) was closed at multiple locations:

- Mile post 211

- Mile post 221

The water was not draining by itself, other than slowly seeping through the roadway base. By running two 800 gallon/minute pumps on the 14th, the pool maintained its level because of the water continuing to run off the hillside into the pool.

On the 15th of April there was no scheduled date of reopening; all traffic was rerouted to HWY 153.

April 25th, they had the water drawn down 20 feet in the pond and continued to pump. Water continued to flow off the mountainside.

May 23rd, there was an estimated excavated area of 400 feet wide as you would travel on the roadway (east/west), 250 feet long (north/south) and 80 plus feet deep.

June 21st, two new culverts had been installed on the Twisp side of the Loup Loup with all excavation being completed of the failed and saturated roadway fill.

On the Okanogan side of the Loup Loup the Westbound shoulder failure and landslide location requited the construction of a rock buttress and the base of the slope. Multiple springs of water flowed out of the hillside above the work area adding to the challenge.

July 3rd, WSDOT was hoping to have one lane open on Monday, July 10th, which would allow traffic to travel over the Loup between 6-9 AM and 4-7 PM.

At this point WSDOT's goal was to reopen the Loup Loup highway as soon as possible, while continuing to do the work in the safest manner possible.

July 10th, Loup Loup Pass opened for travel from 6-9 AM and 4-8 PM.

July 12th, WSDOT's goal was to have the roadway reconstructed at MP 211 (Twisp side) by the end of the day July 14th with no restriction in that area.

July 14th, Loup Loup Pass opened 24/7 with single lane traffic through the MP 221 (Okanogan side) location.

The Loup Loup Pass fully opened: August 16, 2017.

Construction pictures below.

Mile Post 221
Mile Post 221
Mile Post 221
Mile Post 211
Mile Post 211

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