A green smoke grenade is used to signal a UH-60 Black Hawk medevac helicopter during a casualty evacuation exercise near Camp Buehring, Kuwait, Feb. 5, 2015. A green smoke grenade is used to signal a UH-60 Black Hawk medevac helicopter during a casualty evacuation exercise near Camp Buehring, Kuwait, Feb. 5, 2015. SHARE IMAGE: Download Image: Full Size (2.09 MB) Tags: Photo Essays Photo By: VIRIN: 761600-S-KIN89-142.jpg Photo Gallery