Grand Teton, First Ski Descent. William M. Briggs and Robbie Garrett ascended the Grand Teton on June 16 via the couloir between the Petzoldt and Underhill ridges, carrying skis. A single 100-foot rock pitch placed them on top of the Underhill ridge where unbroken snow slopes led to the summit. From the summit the skis were then used to descend to the top of the Underhill ridge. A rappel over the rock pitch permitted an uninterrupted ski descent of the mountain, first down the couloir to the Black Dike, then over to the Teepe Snowfield and down to within 1000 feet of the valley floor where the snow ended.