No quick fix: plan for extended closure on SR 971 Southlake Shore Rd

Before sunrise on Monday, March 3, a rockslide closed SR 971 near milepost 11. This is a spot known for rock fall. By full daylight, it was clear that this slide was a bigger problem than the usual couple of rocks. Then late Monday night, a second slide came down and covered both lanes of the highway again.

A slide at milepost 10.7 overflowed the catchment basins and crossed both lanes of the road on Monday, March 3.

The slide also exposed several large boulders approximately 50-60 ft. above the road. We estimate there’s about 1200-1400 yard of material in the slide. Some of the rocks that came down are too big to haul away without breaking down. Throughout last week, rocks continued to fall, and the slope continued to have active rockfall.

Last week, our geotechnical team met on site with region crews to assess the scene. They met again on Wednesday, March 12 to talk through possible fixes for this location.

It’s not just the current pile of rocks that need to be cleared. This section of road has a history of rock fall, and the current slide location is adjacent to other known areas of frequent rock fall.

Drone pic of the slide area on South Lakeshore Road. The slide is estimated to be 1200-1400 cubic yards of material.

Where we are at?

The team must first consider the safety of reopening the road. During the onsite review, large overhanging rocks were identified still on the slope above the slide. These will need to be removed by scaling. That means having a skilled contractor remove them by hand.

In addition to that, we are heading into spring season. Spring is a time of year when rockslides often increase due to wet and thawing conditions. This means the potential for additional rock fall at and around this location. Spring also brings increased travelers to the Chelan Valley and the Lake Chelan State Park.

What is a fix when it comes to a rock slope?

Repairing the entire section to significantly reduce the risk of rockfall is estimated to cost in the millions of dollars. A project of that scope is not currently funded. Even if we don’t do the full mitigation, any work beyond just a cleanup is likely to be expensive and will mean shifting funds from other priorities.

The team is talking through the pros and cons and reviewing feasible funding strategies.

When will the road open?

We recognize that this detour adds miles to commutes and school bus trips. We’ve discussed the possibility of blocking off the hillside lane and using an automated signal to move travelers through the area one direction at a time. The concern is the continued potential for additional large rocks falling from high up the slope and the barriers being unable to contain them. This would put anyone traveling through that lane at risk.

While South Lakeshore Road is closed, travelers must detour in SR 971 Navarre Coulee Road to the junction of US 97A.

Any fix is dependent on contractor and funding availability. Plan that the road will remain closed, probably for several more weeks. We will post updates as soon as possible, including on our social platforms and the real time travel map.