powder monkey

(informal) An explosives expert. A person who sets explosives.

(nautical) The persons employed to carry gun powder from the ship's magazine to the gun deck during a battle; in the 18th century Royal British and U. S. Navies, this task (also carrying water) during battles became a permanent nickname for the ship's cabin boys and apprentice seamen.

(skiing, snowboarding, informal) A skier or snowboarder who avidly seeks out the “powder” (light, dry, fluffy snow).