On July 22 a party reached the summit of Little Sister via the Grassi Route (northeast buttress) late in the day and chose to descend the way they’d come up because they were familiar with the terrain. During their descent, the climbers set up a rappel from a rock horn. After inspecting the slings in place around the horn, the first climber rappelled to the next anchor. The second climber had begun her rappel when the horn collapsed and she tumbled down the slope. She sustained injuries to her head and torso, but the party was able to descend to a large ledge where they spent the night. They called for a rescue the next morning.

ANALYSIS

The dislodging of natural rock anchors such as horns, chockstones, and boulders is among the most common causes of rappel anchor failure. It is easy to be lulled into complacency by an established anchor, but each anchor must be inspected thoroughly every time. (One way is to pound or kick the rock and observe vibration, movement, or dirt and gravel displacement.) When in doubt, find another anchor or leave a backup. In this case, the common practice of placing a piece to back up the anchor for the first person down would not have prevented this accident, because the horn held in place for the first rappeller but not the second.