May 18, 2009, Chinook Pass Pre-Opening

WA Cascades West Slopes South (Mt Rainier)
Posted by Lowell_Skoog on 5/21/09 6:00am

Kodiak snow blower below Chinook Pass.

On May 18, John Stimberis (Stimbuck) invited me to observe his team carrying out avalanche control work above the Chinook Pass highway.  Since its completion in the early 1930s, Chinook Pass has been cleared each spring by maintenance crews using heavy equipment.  The steep slopes above the road are beyond the reach of the road-bound crews, and snow conditions on those slopes are out of their control.  During the first 50 years of this program, there were enough close calls during the clearing process and after the highway opened that in the early 1980s the Washington State Department of Transportation (WSDOT) decided to apply avalanche control crews to the problem.

In 1983, Craig Wilbour and others from the WSDOT Snoqualmie Pass avalanche forecasting team began assisting highway maintenance crews on the Chinook Pass opening. Initially, Wilbour and his team hiked from the highway to the avalanche starting zones on foot. They started using downhill ski gear (with Securafix touring adapters) a few years later. As alpine touring gear improved, the avalanche crews adopted it for their work. The Chinook Pass program is unique in its reliance on ski-assisted avalanche control work to support highway operations.

Aaron and John begin the climb to Knob 2.

Most of the avalanche control problems at Chinook Pass are east of the pass. There are three main starting zones, called Knob 1, Knob 2, and Knob 3. Knob 1 is a 6240ft peak about 1/2 mile north of Yakima Peak. Knob 2 is a point of similar elevation about 1/2 mile east of Deadwood Lakes. Knob 3 is a bumpy ridge around 6400ft elevation 1/2 mile SE of Sourdough Gap. The 6200ft+ shoulder just south of the ridge is called Picnic Point.

In April, as control work at Snoqualmie Pass tapers off, four people from the Snoqualmie Pass avalanche team move to the Chinook Pass clearing effort. John Stimberis is the supervisor of this team, assisted by Kevin Marston, Aaron Opp, and Lee Redden. On the day of my visit, John and Aaron were working from the east side of the pass (on Knobs 2 and 3) while Kevin and Lee were working from the west side (on Knob 1). At the 2008 ISSW, John" />" />" />

Thumbnails, from left (click to enlarge). One: John points out features on Knob 2. Two: Aaron buries a charge on the south face. Three: John rigs the fuse as Aaron buries another charge. Four: John connects detonating cord to an ANFO bag.

After preparing the shot, Aaron triggered it manually while John and I took video.  I was thankful for the earplugs that Aaron gave me, but concerned when my clothes and camera got showered by burned powder.  John said he's had trouble getting through airport security because his backpack is typically coated with a layer of explosive dust.  He's had to show the screeners his WSDOT identification and blasting license to convince them that he's not some sort of crazed bomb maker.

The Knob 2 shot had fairly minimal results, since the snow in this area has melted and consolidated a lot recently.  We packed up and did some ski cutting to the west, toward the Deadwood Lakes saddle.  Ski cutting is very effective to release surface instability in wet snow, enabling John and his teammates to work large areas quickly.

As we were returning to Knob 2, we watched Kevin and Lee set off a blast on Knob 1 using a timed trigger.  The buried shot triggered a wet slab that swept powerfully over the highway and descended all the way to the valley bottom.  I took a video of the slide, which you can

Highway 410 winds its way up the east flank of Chinook Pass.

Good golly! You can certainly see what all have been saying about the step-down nature of this snowpack in that video! There was much more snow entrained by time it reached the highway than I would have guessed. Can also see why they've learned from experience to leave a cushion of unplowed snow on the downhill side of the road, that's a hell of a firehose of snow when it went over the "jump" of the roadbed.

Lowell, thanks for the insights into what John, Aaron,Kevin, Lee and the crew do to open Chinook Pass.

author=Zap link=topic=13394.msg55774#msg55774 date=1242944151]
Lowell, thanks for the insights into what John, Aaron,Kevin, Lee and the crew do to open Chinook Pass.

Yes, Thank you, Lowell.
And, John,
Thank you so much for going out of your way to help educate the bc ski community on what you folks do at Chinook Pass. Education always seems to me so much better than mandates.
I believe I am not the only one that really appreciates what you do and your efforts to communicate with this community.

^^^^^^ Could't agree more.

I'll third that.  Great TR Lowell.  What a cool opportunity, to witness the crews doing their work.

Really enjoyed the writeup. Thanks Lowell (and to John for offering this kind of access).

A note to John-

This would be a fantastic addition to WSDOT's public blog!

Thank you all for your kind words.  I'm glad to see that a little outreach and education goes a long way with our BC community.


Thanks for sharing this Lowell. The education does go a long way. And I'm glad to see the guys recognized for the hard work they do.  Interestingly enough, we were discussing this several weeks ago and wondering who the "lucky guys were" that got paid to spend their day ski cutting and detonating for Chinook Pass... had no idea you were one of them Aaron. :) Thanks so much.

Was up around Norse Pk on Monday.  Could feel the blasts in our bones.


author=jhamaker link=topic=13394.msg55803#msg55803 date=1243005060]
Was up around Norse Pk on Monday.  Could feel the blasts in our bones.


Here's the link I included in my initial post. It gets kinda lost if you skim the post:

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2009-05-21 13:00:19