California, Yosemite Valley. On June 17th Charles Stanbrough (age 19) set out to solo the Steck route on Higher Cathedral Spire. The next day his body was found at the base of the route. He did not sign out and none of his friends had missed him. (Source: Peter Thompson.)

Analysis: Stanbrough was using a 9 mm perlon rope and a 3/8" Goldline prussik loop for self-belay. Apparently an aid placement failed about 180 feet off the ground. The faulty aid placement and the use of an old rope reflect Stanbrough’s judgment, but probably he did not realize that his self-belay arrangement almost certainly would not work. The principle of the prussik knot requires that the prussik loop rope be of distinctly smaller diameter than the climbing rope. Perlon of 9 mm and 3/8" Goldline are virtually the same diameter. The problem is compounded when the prussik loop is of a relatively stiff rope that tends not to grip of its own accord. Common sense dictates that the prussik loop should have a reasonable diameter for safety’s sake, which in turn means that in most prussiking situations 11 mm perlon or 7/16" Goldline will be the climbing rope preferred.