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Salt Lake » Big Cottonwood Canyon » Mill D South » Kessler » Argenta

Argenta

10,000'

North

37°

Skier

Unintentionally Triggered

Soft Slab

Persistent Weak Layer

Facets

2'

50'

700'

1

Beautiful day in the Wasatch. Our party of 3 experienced backcountry skiers set out just before 0500, skinned up Argenta, skied a mellow line on the Catcher's mitt, booted up the East Couloir, and opted to ski back down Argenta instead of the East Couloir for much better snow quality. We descended the ridge west from the top of Kessler, careful not to dip into the steep terrain on either side. As I was skiing the trees of the ridge around 10,000ft, I hit a rock garden that had been covered by the new snow. This caused me to lose my ski and fall onto the low 30s degree angle slope which rolled over into a slope which appproached 40 degrees much further downhill. I stood up and began probing for my ski, which appeared to have torpedoed about 5 feet below me. I stepped a few feet below where I had landed--I would guess that the slope was 35 degrees at that point--and felt the slab begin to slide beneath me. It broke out 3-5 feet above where I was standing. Luckily, I was standing by a tree and was able to grab onto a limb, which allowed me to pull myself up while the ground gave way. The other members in my party were luckily still on the ridge and out of the way. The slab was quite cohesive consolidated new snow. The interface at which it slid did not appear faceted or rotten. It broke out around 50 feet across and funneled down over a large cliff. The impact of the avalanche falling over the cliff propagated another slide, with a crown that appeared to be 4-5 feet. I watched from above and shouted warnings as I saw the slides continuing downhill. As we were not sure if anyone had been caught or carried, my two partners left me quickly and found a safe way down to the debris. There they encountered a party of two who watched the slide and did not believe there were any other parties ascending or descending between us. My partners performed a beacon search and found no buried persons. As one of my partner's phone was dead and the other on airplane mode, I no longer had contact with them and I did not know whether there were any injured parties. As such, I snapped a few quick pictures of the crown, but did not have time to thoroughly investigate it. I descended via the skin track on one ski until I reached mellower terrain (apologies to anyone skinning up later...). I reached my partners at the base of the debris and saw that the other two parties were approaching the lower, 4-5 foot crown to investigate (perhaps they will post photos). Note: if anyone finds a BD Amperage ski with Dynafit bindings in the debris, I would love it back. Please contact UAC if found. Beer and good karma in it for you! My take on the incident: The same three skiers in our party lapped Cardiff peak yesterday and noticed some mild sluffing underfoot and also visualized moderate soft slab natural avalanches on two trees. We were aware of the rapid loading which took place and knew the avi forecast well, and knew that there was potential for activity today. We checked out the dawn patrol forecast and were aware of the recent natural avalanche cycles down south and potential for slab activity on steep north-facing slopes. We planned to ski the Catcher's Mitt and did so at the lower angle route. We planned to ride the ridge from Kessler west until we reached more moderate terrain before dropping in. I had no intentions of skiing where the avalanche occurred. I was incredibly fortunate to have a tree beside me which I was able to grab onto. Otherwise I may well have ended up at the bottom of a very large cliff. I did not expect the new snow interface to give so easily and on a relatively moderate roll-over, but the steeper terrain below the rollover was sufficient to release the slab. I considered the risk of descending another few feet to retrieve my ski, and felt that an avalanche was highly unlikely based on this action. I was wrong. Lessons: We saw red flags today: recent loading, evidence of natural avalanches out in the distance in Broad's fork. There was no collapsing or cracking that I noticed, and no slides apart from gentle sluffs and warm releases of of Kessler. I knew there were pockets of considerable and unfortunately I literally fell right into one. It turns out that trying to make smart decisions with regards to route choice only works most of the time, and you need to be prepared for the worst and hope to get lucky if badness happens. One of my partner's injured her knee in the backcountry a couple months ago and required extrication. A few of us were able to splint her leg, keep her warm, and extricate her using skins, skis, cordelette, athletic and duct tape, and Voile-style ski straps. Because of accidents like that, I always carry extra layers, an emergency bivy, ski straps, tape, and pain meds. I feel that had there been an injury or burial, my party would have been prepared to respond. One thing that could have gone better, however, is communication. With phones not working, it was impossible to communicate. This underscores the essential need to carry either a phone or radio that is functional. UAC's iPhone App was awesome for pulling up Alta Central and UAC numbers to report the incident. Thanks to UAC for all your life-saving work.