Red Mtn - ESE Chute
Tuesday, February 26, 2019 - 9:15am
The following is a summary of a verbal report from skier who triggered old hard slab avalanche on Tuesday 2/26/19:
We climbed the eastern slopes of Red Mtn from Rock Creek Rd. to summit. Winds were strong and swirling, but didn't lead to any significant deposition anywhere that we could find, mostly just scouring winds. We noted old partially buried avy debris in the chute just south of the one we chose to ski. The surface of the snow in the upper bowls was stained with old pine needle leach from melt freeze cycles over the previous week. Today was cold though and windy, we were bundled in puffys. Air temp was in the 20s. Before dropping in, my partner posted up on the ridge in a safe location with good visibility of the slope. We talked about our plan to ski the slope one at a time and leap frog down.
I entered the chute that drops into Aspen Park campground from the north side and ski cut across the upper slope just below the corniced ridge. The slope was hard refrozen snow, chattery with barely any ski penetration. Nothing released with my ski cut. About 6 turns down, the snow was still very firm and chattery. I was making a left turn when cracks shot out from my skis in both directions. I looked over my left shoulder and saw that the entire slope had fractured and was sliding. I was able to ski out left ~20’ into the trees on the left edge of the slope and was fortunately able to continue traversing further to the side even more to avoid being caught. The crown appeared to be 8” with some deeper sections perhaps up to a foot and ~100’ wide. There were couch pillow sized blocks that were thicker. It was an old, hard slab that accelerated quickly and slide over 1400’.
I don't think I would have been buried had I been caught, but definitely would have been taken for a nasty ride and likely been hurt.
This was quite an eye-opener, as there were no indications of current instability. We have been skiing similar aspects at similar elevations. Obviously there was still a weaker layer lurking on this slope. It was a very good reminder how important it is to always ski with proper protocol, one at a time, even when slopes feel super bomber and locked up. I do wish we had taken some time to better evaluate the snow below the cornice. This likely would have revealed that the icy surface was only skin deep.
Forecaster comments: We don't know what the weak layer was that was involved in this slide. A best guess is that there was an old melt-freeze crust that formed some days ago, perhaps some minor faceting occurred on this crust, winds picked up and loaded snow on top of this crust, then more days of melt-freeze occurred giving the impression of a locked up slope. Glad they skied one at a time and that the skier was fortunately near the side and able to ski out of the way! Also a good reminder that trigger points can be towards the edges where slabs are thinner.