Ice Screws. On the Nisqually Glacier in early June we had the chance to check and compare MARWA ice screws (AAJ, 1962, 13:1, p. 287) with the lag-screw type and also with wedge and tubular ice pitons. I was most impressed with the ease in which the small diameter MARWA piton can be placed into the ice, even black ice. No hammer is required as it can easily be screwed in with the hand, with perhaps a carabiner for leverage. The long pitch allows it to be installed in a minimum of time. All other pitons require hammering, which of course means carrying additional weight and equipment. Our heavy ice screws required a great deal of pounding. In one experiment we placed different types of pitons in relatively old ice where the pitons were exposed to the sun. We could pull the tubular type out in 4 minutes, the wedge types in 10 to 11 minutes and the MARWA in about 20 minutes. The lag-screw type never did weaken sufficiently in half an hour so that we could pull it out. All pulls were made straight out. We climbed an overhang of about 12 or 15 feet, using tubular, lag-screw and MARWA ice screws. The tubular were useless and pulled out in the first few minutes. Both the screw types were satisfactory but had a tendency to shear down in the ice, probably because of force and warm air temperatures. We were at 6500 feet on the flat of the glacier and the air temperature was high. Perhaps this problem would be less severe at higher elevation in colder air. Obviously since the larger screw has a greater diameter, it did not shear as rapidly, although the difference between the two was not great. (The editor also used both types of ice screws for direct-aid climbing in the Cordillera Blanca of Peru and found them both excellent, each with its own advantages. The lighter and more easily placed MARWA were preferred except where it appeared that the longer and thicker lag-type gripped better in porous ice.)

Peter K. Schoening