A row of Alabama National Guard field litter ambulances wait as guardsmen, from 129th Area Support Medical Company, 161st Medical Battalion, 167th Theater Sustainment Command, out of Centreville, Ala., Aug. 9. The guardsmen conducted evacuation and ambulance training during Vibrant Response 13, a major field training exercise conducted by U.S. Northern Command and led by U.S. Army North. The training is focused on military units and civilian forces that respond after a domestic natural or man-made chemical, biological, radiological or nuclear disaster.