Capt. Jeff Rees, 321st Missile Squadron flight commander, reaches up to insert his hand into a crevice in the side of a rock wall at Vedauwoo, Wyo., Aug. 28, 2013. When climbing rock faces with few hand holds and many suitable crevices, jamming, a method of climbing by wedging one’s hands into the crevice to gain traction is a useful method. (U.S. Air Force photo by Airman 1st Class Jason Wiese)