Sgt. Eric Masters, mountain leader instructor, Marine Corps Mountain Warfare Training Center, conducts a weapons check before going to the night vision live-fire range aboard the training center, Feb. 20, 2014. During the day the Marines traveled long distances, and at night coordinated battle skills while on the same challenging terrain. - Sgt. Eric Masters, mountain leader instructor, Marine Corps Mountain Warfare Training Center, conducts a weapons check before going to the night vision live-fire range aboard the training center, Feb. 20, 2014. During the day the Marines traveled long distances, and at night coordinated battle skills while on the same challenging terrain.

Headquarters and Services Company, 2nd Battalion, 7th Marine Regiment, Marines take a pre-environmental training class at Marine Corps Mountain Warfare Training Center April 2, 2012. Field classes familiarize the Marines with their new environment. - Headquarters and Services Company, 2nd Battalion, 7th Marine Regiment, Marines take a pre-environmental training class at Marine Corps Mountain Warfare Training Center April 2, 2012. Field classes familiarize the Marines with their new environment.

Petty Officer 3rd Class Salvador Bautista, a corpsman with Company I, 2nd Battalion, 4th Marine Regiment, maneuvers through the snow at Marine Corps Mountain Warfare Training Center Bridgeport, Calif., near the Goose training area to set up a warming station during a Cold Weather Medicine Course Jan. 14, 2009. - Petty Officer 3rd Class Salvador Bautista, a corpsman with Company I, 2nd Battalion, 4th Marine Regiment, maneuvers through the snow at Marine Corps Mountain Warfare Training Center Bridgeport, Calif., near the Goose training area to set up a warming station during a Cold Weather Medicine Course Jan. 14, 2009.