Eric L Bilderback, National Park Service, Geologic Resources Division, Lakewood, CO, United States, Douglas A Anderson, Federal Highway Administration, Western Federal Lands, Vancouver, WA, United States, Simeon Caskey, Grand Teton National Park, Physical Science, Moose, WY, United States, Robyn L Henderek, Zion National Park, Resource Management and Research Division, Springdale, UT, United States and Jeffrey R Moore, University of Utah, Geology and Geophysics, Salt Lake City, UT, United States