Monday, January 5, 2009

Why we close the pass...

We have received a lot of curious emails lately asking us why we close the mountain passes when there is risk of avalanche danger. I could tell you, but I thinks that these photos will tell the story better. When you see what an avalanche looks like and consider the danger of being buried by one, you can see why we take the closing of the passes very seriously.

Stevens Pass - February 2008 - Tunnel Creek

Snoqualmie Pass - January 31, 2008 - Cars stuck in both sides of avalanche
Did you know that there are at least 40 avalanche chutes on Snoqualmie pass alone!

SR 20 - January 2008 - Newhalem - Not just snow comes down in an avalanche, sometimes rocks do too.

SR 20 - January 2008 - Aerial View - Newhalem slide

Typical Avalanche at Snoqualmie Pass East snowshed - an avalanche of this size can cause the pass to be closed for two hours.

As you can see there is considerable risk to any vehicle that tries to cross the mountains when these dangerous conditions exist. We appreciate your patience while we take the appropriate time to make sure the highway is safe for travel.


Anonymous said...

The Seattle P-I has a good story today about the Snoqualmie Pass avalanche crews with photos.

Anonymous said...

It's amazing what power the light fluffy stuff can do. But I always wondered why a snow tunnel was built over only the west bound lanes of I90, leaving the snow to dump on the east bound lanes.

Jeremy Bertrand said...

When the east snowshed was rebuilt in 1950, I-90 was only a two-lane highway. Several years later, I-90 was expanded to four lanes. There is no documentation that explains why the snowshed was not expanded at that time. We do have plans to update the snowshed with the I-90 Snoqualmie Pass East Project. The snowshed will cover all six lanes of the highway, and be twice the length of the existing shed. These improvements will reduce the amount of avalanche-related closures in the project area at the pass.

Anonymous said...

I have no hard numbers but feel comfortable stating that the number of hours closed each winter has skyrocketed the last two years. I am willing to be educated if that is not the case. Last year was a great snow year, but it was not bigger than the record snow year of 98/99, and I was commuting over the pass and don't remember so may days being shut down.
I really don't want to be too critical, because I understand the enormous responsibility. However it seems good critical evaluation has been replaced with "just shut it down" mentality.
in defense of WSDOT, I do remember a car getting swept over the side of the highway in 98/99 at Stevens. So go figure
My question: has there been a big increase in the number of hours shut down, and if so what has changed.

Anonymous said...


Excellent posts as usual. Quick question when you mention avalanche chutes what exactly are those?

Perhaps pre-determined routes man-made that ensure snow comes down in certain areas or just over time it's constantly the same area?

Anonymous said...

This is my guess.

If only WSDOT could control the weather...

Anonymous said...

You mean the pineapple express first hit the shores of Washington last year?

This major event is not the only event to cause a closures this year. The current closures are understandable, the mountain are crumbling around us. My early post was more concerned with the lengthy avalanche closures. I remember in the 98/99 winter a avalanche had occurred at old faithful on Stevens, and the DOT had the pass open before the road was finished being cleared. NO exaggeration,the west bound lanes were covered with snow, and while the front end loader cleared the west bound lane both directions used the east bound lanes.

Anonymous said...
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