KNOT CAME APART–FALL ON ROCK, INADEQUATE PROTECTION

Utah, Ferguson Canyon, Mission Impossible

On July 19, “Dan” (25), and “Jim” decided to beat the heat in the Salt Lake valley by climbing in cool, shady, Ferguson Canyon. Dan scrambled around to set up a top-rope on Mission Impossible, a 5.9 crack on the Cathedral. He clipped quickdraws to the two bolts at the top. Then, concerned about rope drag on the rock edge, he extended the anchor with a single piece of tied webbing. It was a long way from the bolts to the edge, and he had only one long sling, so he did not back up his anchor. He threaded a figure-eight device onto the ropes and started to rappel. Shortly after he backed over the edge, the knot in the webbing failed, and he fell 50 feet to the ground.

Dan was conscious and alert but suffering from two open lower leg fractures and a fractured wrist. He was immobilized in a bean-bag vacuum splint and carried out to the Ferguson Canyon trailhead, where he was loaded on a Lifeflight helicopter and flown to the hospital.

Analysis

The knot that parted was a water-knot, or overhand follow-through. The knotted sling that came undone had held body weight before. Dan guessed that he had ten days of climbing on it before the day of the accident. He did not check it carefully before his rappel.

Water knots can fail by gradually ratcheting under repeated body-weight loads. The tails get slightly shorter each time it is loaded. When the tails have ratcheted all the way into the knot, the knot comes undone. The accident could have been prevented if he had rigged a redundant anchor that was not dependent on a single piece of webbing. (Source: Tom Moyer, Salt Lake County Sheriff’s SAR)