American Alpine Jounrna and Accidents in North American Climbing

Rockfall – Anchor Chopped

Utah, Little Cottonwood Canyon, The Thumb

  • Accident Reports
  • Author: Carl Dec
  • Accident Year: 2015
  • Publication Year: 2016

On February 14, Carl Dec (48), Morgan Lavery (33), and Billy Smallen (33) were enjoying unseasonably warm and sunny weather on the Standard Thumb route (III 5.7) on the Thumb formation. The three climbers were very experienced, each of them certified climbing guides. The trio had climbed the first two pitches of the route and were preparing to start the Indecent Exposure variation (5.7), a well-traveled alternative to the fourth and fifth pitches. Dec and Smallen were both attached to the anchor with the rope, clove-hitched to the master point of an 8mm Dyneema sling that was clipped to the two-bolt anchor and extension-limited with an overhand knot. As it was a spacious stance, they both were anchored with tethers between six and eight feet long.

Lavery began leading the first pitch of Indecent Exposure and was climbing through a section of double cracks when a large block dislodged. The block fell for approximately 30 feet before landing in the gully above the belay and exploding into various pieces.

Dec had scrambled up a short ways and was standing with his feet even with the anchor when the rockfall came down. He was hit in the legs and knocked down, ending up in the corner of the alcove, on his back, with a block on his chest. Smallen was able to pendulum off the anchor to the right and avoid being hit, but then swung back on the anchor after the rockfall passed.

At this point, Dec and Smallen were both hanging with their full weight on the anchor. Dec looked up to see that the rockfall had completely severed one leg of the anchor sling, and both climbers were now hanging from the master point with the intact leg of the sling clipped to the other anchor bolt. In addition to half the anchor sling being cut, the group’s two ropes suffered a total of four core shots, and both belay bolts and the biners that were attached to them were smashed to varying degrees. After assessing Dec’s injuries, the climbers added gear to the anchor and descended.


Anchor construction and connection is often debated, but in this scenario there is no question that clipping the master point of a redundant anchor, which would not extend, saved two lives. If a sliding X (a.k.a. magic X) had been used to equalize the sling or cordelette, without extension-limiting knots, the anchor likely would have failed completely and the climbers likely would have been killed.

Weather may have contributed to there being a loose block on this well-traveled route. The winter in Utah started off cold and wet and then went dry and warm. There was a substantial freeze/thaw cycle in the canyon that may have been enough to loosen the large block. In such areas it’s good to be wary of loose rock early in the season. (Source: Carl Dec, Red River Adventures.

Note: An interview with Carl Dec is featured in Episode 7 of the Sharp End podcast.

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