FLYING chips of ice sparkled in the July sun as I hammered a pick into the 1,200-foot-high sheet of ice and snow called the Dana Couloir in Yosemite National Park. I was suspended on the side of a mountain in a couloir, an icy gully, by the points of my crampons and the ice axes I held in either hand. Couloir climbing is a summer sport in the Sierra Nevada, but it might not be around much longer.
http://travel.nytimes.com/2009/08/21/travel/escapes/21iceclimb.html