powder monkey

Short definition from Wiktionary

Noun

1. 1
   An explosives expert; a person who sets explosives.
2. 2
   A person 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.
3. 3
   A skier or snowboarder who avidly seeks out the “powder” (light, dry, fluffy snow).