Brostrom and the rest of the soldiers from the 17th Infantry were not trained or properly equipped for Arctic combat on Attu, for in those days the U.S. Army knew practically nothing about waging extensive winter warfare. Nevertheless, Brostrom and his fellow soldiers from the regiment carried on, and for this action they won a Distinguished Unit Citation. During the battle, Company F's attack in the pass between the valleys was magnificent. The GIs used rifles, bayonets, and hand grenades to drive the enemy out of a series of trenches near the vital Cold Mountain. The fight for the island culminated in a battle at Chichagof Harbor, where the 7th Infantry Division destroyed all Japanese resistance on the island on May 29, after a suicidal Japanese bayonet charge. The 17th Infantry then invaded Kiska expecting another serious fight, but Brostrom and the others of the regiment found out that the Japanese had evacuated the island prior to the American landing.