Traffic Payout

By guest blogger Summer Derrey

Have you ever played the hold-your-breath game on road trips? I remember traveling from Yakima to the Pacific Science Center in Seattle as a kid with my fellow Campfire gal-pals.  We held our breath when we went through the I-90 snowshed, sure it was only for 500 feet long but it kept us entertained.

Crews building the snowshed in the spring of 1950.

As much as the shed was a part of my childhood, I’m sure many other people shared similar experiences, from singing car songs to playing the I-spy game. If you were around in 1950, you may have watched construction of the shed while riding the train on the other side of Keechelus Lake.

After 64 years of dutiful service, the old snowshed is coming down, and I’d like to take this opportunity to pay a little tribute by inviting you to learn a bit more about the background of this historic snowshed.

Formally called the Keechelus Snowshed Bridge, “the shed” was built in the spring, summer, fall and winter of 1950 to protect drivers from avalanches. The 500-foot-long shed is 34 feet wide and has a concrete roof supported by a 30-foot-tall, 15-inch-thick retaining wall that hugs the hillside. The roof span consists of 200 precast concrete T-beams. The sides are detailed with false portal fronts bearing art deco detailing. You may recall the 1950 stamp on each side.

In the 1950s and 1960s, US Route 10 over Snoqualmie Pass was widened to four lanes. Also during this time, state highways were renumbered to meet the American Interstate Highway System, creating what we know now as Interstate 90. While I-90 expanded, the snowshed continued to only cover the two westbound lanes. There are a number of factors why the shed wasn’t changed to accommodate increased traffic back then – mostly design challenges.

Snowshed during a nice winter’s day.

In 1995, the Keechelus Snowshed Bridge was placed on the National Register of Historic Places list. It represented the first time precast construction was used for a highway structure in a mountainous area. It is the only interstate snowshed remaining. Another snow shed was built on the eastbound lanes of I-90, west of the summit, but that came down in the 80s.

And now, it’s time for our contractor, Atkinson Construction, to remove the snowshed and replace it with avalanche bridges as part of the I-90 Snoqualmie Pass East project. The elevated structures will allow snow to slide under the bridge between the bridge piers. That’s good news – crews won’t have to close the pass as often in the winter for avalanche control work.

Aerial view of the snowshed in summer.

Although the snowshed is coming down in April, it has plans for retirement. Most likely the shed will be recycled and used as extra material in other parts of the I-90 project.

Perhaps I’ll stay busy by creating a new hold-your-breath game traveling up and over the raised avalanche bridges. I’ve got a few years to develop the idea. Construction of the new bridges is scheduled to begin this spring and be complete in 2018 when construction on the rest of the widening project is complete.