The Liberty Ridge Route, grade IV, is a considerably more challenging and objectively dangerous route than the normal route to the summit. It runs up the center of the North Face of Mount Rainier and crosses the very active Carbon Glacier. First climbed by Ome Daiber, Arnie Campbell and Jim Burrow in 1935, it is listed as one of the Fifty Classic Climbs of North America by Steve Roper and Allen Steck. This route only accounts for approximately 2% of climbers on the mountain, but approximately 25% of its deaths.