Sunday, February 18, 2007

My First Whoompf-ing Experience

I went ski touring yesterday morning for the first time in probably a month. Winter here hasn't really been winter and the snowpack was just faceted crystals the whole way through. We've recently had a few, small systems come through and give us more of the good stuff.

Matt and I headed up Big Cottonwood Canyon at about 6 am. Since the avalanche danger was rated "considerable" in most areas we decided to hit up some low-angle, sheltered aspects. We started touring up Mill D to a small slope that is covered in aspens. We'd skied here before and it is a relatively safe slope. Our first run went off without a hitch. The turns were smooth and nice. The new snow was dense and provided some buttery turns.

After reaching the bottom we decided to make another lap. We skinned back up to the top of the short shot we previously hit. From there we wanted more vert so we started up an adjacent peak. Being concerned about safe travel, we quickly made our way to a ridgeline and made our way up. About halfway up the ridge become choked off by trees and deadfall. This forces us just off to the side of the ridge. We hugged the trees as close as we could and continued towards the top.

At one point the trees ended and we started making our way back up to the ridge. We were close together and in a somewhat open area when we heard a loud "Whoompf". We stopped dead in our tracks, listened intently, and looked around. The "whoompf" sound is made when one layer of snow collapses onto another layer. This is a sure sign of instabilities in the snowpack. With my heart now racing I scanned the snow to find a few small fractures that had propagated a few feet.

Avalanches can occur when a strong layer is sitting on top of a weak layer. The weak layer then fails and the strong layer comes ripping down the mountainside. When that weak layer fails, the strong layer then collapses through the weak layer and the sound you hear is "whoompf".

We quickly made the decision to spread out and get off the aspect we were on. Since Matt was breaking trail he continued while I moved back to a couple of small trees. Once Matt was on safer ground I moved up to meet him. We then proceeded, one at a time, up the ridge some more to dig a pit. We dug a quick pit and did some simple shear tests.

From here we were less then a minute from the ridgeline so we prepared to move up to it. As Matt started moving, we once again heard a loud "whoompf'. This time, however, I dropped a couple of inches. It could have been because I was standing right where we dug the pit, it could have been that I was standing on snow that was on top of bushes. Whatever the specific cause, it once again made my heart start pounding. I moved over to a large aspen, just in case, while Matt skinned to the ridge. I then quickly and very carefully joined him.

We decided our best bet for a safe ski down was to make a quick traverse over to an aspect similar to the one we had previously skied. The decision was sound and we enjoyed some very smooth, fun turns through an aspen grove back to the skin track. We skied one at a time from island of safety to island of safety. Within a couple of these short skis I had some of my best turns of the year. The last section was the longest and the best. I just happened to pick an awesome line.

After a very short and fast descent down the skin track we were back at the parking lot. It was a fun, extremely eventful, and educational morning.


Mrs. Olsen said...

That sounds scary! Although it sounds like you had fun in the end, too.

Mrs. Olsen said...

That sounds scary! Although it sounds like you had fun in the end, too.