A term in
mountaineering describing the use of
speed and self-contained tactics. The idea is to climb the
mountains without leaving any traces.
This includes light-weight equipment, calculated food rations and no outside help. The climbers usually bring all their ropes with them until the final push for the summit, when they leave everything except the most necessary at a camp. Alpine style climbing often means that no supplementary bottled oxygen is used.
This style was popularized by famous climber Reinhold Messner, among others during the 70's.
Alpine style is something completely different from siege tactics.