Marine Corps Lance Cpl. Kwan Walker faces the elements during a conditioning hike as part of exercise Ullr Shield, which trains Marines in extreme cold environments, at Fort McCoy, Wis., Jan. 13, 2018. Marine Corps photo by Lance Cpl. Cody Rowe
Sailors move simulated casualties during firefighting and mass casualty drills on the USS John C. Stennis in Bremerton, Wash., Jan. 10, 2018. The Stennis is in port conducting routine training. Navy photo by Petty Officer 3rd Class William Ford
An MH-65 Dolphin rescue helicopter medevacs an ill fisherman from the Coast Guard Cutter Willow about 60 miles east of Atlantic City, N.J., Jan. 11, 2018, to a regional medical center. Coast Guard photo by Petty Officer 1st Class Seth Johnson
Army Capt. Christopher Young engages with a civilian role-player during a training exercise at Fort Polk, La., Jan. 15, 2018. The training prepares service members for deployment to Afghanistan. Army photo by Staff Sgt. Sierra A. Melendez
Air Force Airman 1st Class Kaylon Thomas, a security forces officer, fires an M249 automatic weapon at a target during a machine gun qualification at Joint Base Elmendorf-Richardson, Alaska, Jan. 10, 2018. Air Force photo by Justin Connaher
Airmen and soldiers compete in the 5th annual Army vs. Air Force hockey game, which enhances the relationship between Joint Base Elmendorf-Richardson and the community, in Anchorage, Alaska, Jan. 13, 2018. Air Force photo by Justin Connaher
Navy Petty Officer 1st Class Cory Webb kisses his wife, Deborah, as the USS Chafee returns to Joint Base Pearl Harbor-Hickam, Hawaii, Jan. 12, 2018, after maritime operations. Navy photo by Petty Officer 2nd Class Justin R. Pacheco