Tuesday, October 13, 2009

Massive landslide closes SR 410 near Naches

By guest bloggers Joe Irwin and Megan Pembroke

Drivers who use SR 410 near Naches are facing a traffic nightmare after a massive Oct. 11 landslide blocked a half-mile section of the roadway. The slide was powerful enough to demolish the highway and carry tons of dirt, pavement, and debris into the Naches River, shifting it off course. That new course took it right over the Nile Loop Road on the other side of the river, cutting off another access point for local residents.

Long-time WSDOT engineers tell us that a slide of this scale hasn’t been seen in the last quarter century. That means that efforts to restore transportation to the area won’t be easy. We’re extremely grateful no one was hurt in the slide, but we also know that the aftermath is incredibly frustrating for nearby residents and businesses.

As the Department of Natural Resources explores the cause of the slide, we’re focusing on restoring temporary access to the area. We’re particularly concerned about providing residents of the nearby Nile Valley community with a safe route to jobs and services in Yakima. It’s currently taking them an additional two hours to get there. 


Today we began building a temporary road to restore emergency services and limited local access for the 600 homes and businesses along SR 410. Crews are working quickly, but the work will be slow-going. They must install several culverts and build up the roadway with fill material and crushed rock before it can be opened to traffic.

Drivers who rely on SR 410 have been contending with a major detour since the weekend. To keep drivers safe, we initially closed a 47-mile section of SR 410 following the landslide Sunday. Today we moved the closure points closer to the landslide, allowing access to all but a four-mile section of SR 410. The highway is now closed between the east and west intersections of Nile Loop Road (mileposts 104-108).

However, you won’t be able to get all the way across the state on SR 410, so if that’s your goal, plan to take alternate routes like I-90 Snoqualmie Pass or US 12 White Pass and SR 123 Cayuse Pass. Be sure to check for lane restrictions for construction projects before you head out.

What’s next?
We have a long road ahead of us. Forecasts are calling for snow in the area, so we’ve lined up plows and crews on both sides of the closure. We’re still dealing with an unstable slope and facing an immense mountain of dirt and debris where a highway used to be.

Houses and highways can be rebuilt, but not a life.  With that in mind, we’ll proceed with extreme caution to ensure that safety remains our top priority as we begin to explore our options for a long-term fix. At this time, we don’t expect to open SR 410 west of Naches this winter.

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4 comments:

roundabout said...

Thanks for the update. I suggest that someone post a map on-line that shows the location of road closure and detour routes.

Erica Mulherin said...

The project web page has a map of the closure points.  There is no detour.

Folks can reach the area WEST of the slide by traveling SR 410 EB or US 12 to SR 123 to SR 410.  You cannot drive west of the slide from the east at this time.  We are working on raising the existing county road above the new river back water to establish through access for local residents (ID required) and emergency services.

sbond56 said...

Does anyone recall back in the 1980s the strange ice formation that was uncovered in the side of the mountain that slid? I can't recall all the details but it had something to do with gasses? It was uncovered during digging by Simmon's construction. I seem to recall that scientists came from WSU or maybe UW to look at it. Could this shed light on why/what happened with that mountain?

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