The ground erupts at the Sailor Creek Range at Mountain Home Air Force Vase in Idaho Oct. 2, 2013, after a U.S. Navy AV-8B Harrier aircraft drops a simulated bomb on target during exercise Mountain Roundup 2013 131002-F-WU507-208

The ground erupts at the Sailor Creek Range at Mountain Home Air Force Vase in Idaho Oct. 2, 2013, after a U.S. Navy AV-8B Harrier aircraft drops a simulated bomb on target during exercise Mountain Roundup 2013. Mountain Roundup is a multinational exercise focusing on ground operations, close-air support, urban combat, convoy operations and air-to-air training scenarios.