On 1.24.10 we triggered a pretty sizable avalanche while backcountry skiing at wolf creek pass. Everyone wants to hear all the details, so here it goes...
Wolf Creek Pass had gotten approximately 65" in 4 days, but the storm had passed and it was beautiful out, still winds and blue skies. We began from the trailhead near the pass summit and skinned to the bench between the two "radio tower" mountains (no idea what the locals call them). From here we cut right and headed for the southern radio tower mountain. The bowl that drops off to climber's left has everything from northeast to south-facing terrain and about 600' elevation loss. We had been assessing the snowpack during the approach; there was about 3' of light powder from the big storm, on top of the old base, which seemed to be pretty variable in terms of thickness and density. Below the old base layer was a layer of hoar, of variable depth. From the top of the bowl we picked what we thought would be the safest line, a spine with trees, and traversed to the drop-in. We dug two reusch block pits about 15 meters apart. Both tests did show layer shear, but only after significant force was applied by the skier, and in more of a 'crumbly' rather than a 'clean-break' fashion. We spent another few minutes ski-cutting the starting zone. There were no signs of fracturing, no whoomping or settling, and minimal slough. Of course we had been reading the Avy forecast and were wary, but we were surprised but the apparent stability of the snow, and made the decision to ski. On our second run we worked our way clock-wise around the bowl to another spine. On our third run we came counter-clockwise along the ridge and dropped into an east-facing slope, through some pretty thick trees.
I skied first and then carried my speed across the gully and up the opposite side. A minute later and I'm filming Vince. I was so totally focused on keeping the camera steady and keeping Vince in the screen that I didn't notice the slide right away. The first thing I recognized was this surreal noise, of all that snow moving, and a low-pitched rumble or drone. Before I looked up from the viewfinder I realized what was happening. I ditched the camera (after pushing 'stop' apparently) and made to kick turn and traverse away (hopefully far away). I turned uphill and yelled at Vince, who was cruising to a stop above me. He didn't realize yet what was going on. It was difficult to judge how far the snow would run up the opposite hill, and for a second I panicked. Another couple seconds and it was obvious that the main flow of snow would miss us both, which was sweet. Below find links to some pictures of the slide and the starting zone, etc.
The slope of this bowl is about 35 degrees in most spots. The slide was triggered by our second skier on our third run of the day. The main crown looks to have run to the ground, the picture is about 30 meters looker's left of our drop-in spot. We estimated the crown at 100 meters wide. Interesting to note that it triggered fairly late in Vince's run. You can see in the video that the trees on this run are fairly thick, and I always equate tight trees with improved safety in my mind, but that was obviously not the case on this day.
Video (watch it in HD!)
I have more footage and I'll try to get it up soon.
