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Failure of Bolt Anchor, Alberta, Rocky Mountains, Cascade Mountain

FAILURE OF BOLT ANCHOR

Alberta, Rocky Mountains, Cascade Mountain

Cameron Cairns (20) and Randy Clark (24) had climbed Cascade waterfall on 3 March 1978 and were rappeling down it. Cairns descended about 30 meters to easy slopes. Clark followed him, but when he was about a third of the way down the anchor failed. He fell about 20 meters, then tumbled some hundred meters further down hard snow and was killed immediately. (Source: T. Auger)

Analysis

The rappel anchor was a single 3/8-inch sleeve bolt with a drilled Cassin pin for a hanger. It failed when the limestone around the bolt cracked away leaving a discshaped depression. It is bad practice to trust a single anchor, and this is especially so in the friable rock of the Rockies. There was another bolt nearby and, though it would have been hard to reach and would have required several feet of sling, it could have been used. (Source: T. Auger)