Mountaineering is the sport, hobby or profession of walking, hiking, trekking and climbing up mountains. It is also sometimes known as alpinism, particularly in Europe. While it began as an all-out attempt to reach the highest point of unclimbed mountains, it has branched into specializations addressing different aspects of mountains and may now be said to consist of three aspects: rock-craft, snow-craft and skiing, depending on whether the route chosen is over rock, snow or ice. All require great athletic and technical ability, and experience is also very important.

Snow

While certain compacted snow conditions allow mountaineers to progress on foot, frequently crampons are required to travel efficiently over snow and ice. Crampons have 8-14 spikes and are attached to a mountaineer's boots. They are used on hard snow (neve) and ice to provide additional traction and allow very steep ascents and descents. Varieties range from lightweight aluminum models intended for walking on snow covered glaciers, to aggressive steel models intended for vertical and overhanging ice and rock. Snowshoes can be used to walk through deep snow. Skis can be used everywhere snowshoes can and also in steeper, more alpine landscapes, although it takes considerable practice to develop strong skills for difficult terrain. Combining the techniques of alpine skiing and mountaineering to ascend and descend a mountain is a form of the sport by itself, called Ski Mountaineering. Ascending and descending a snow slope safely requires the use of an ice axe and many different footwork techniques that have been developed over the past century, mainly in Europe.

The progression of footwork from the lowest angle slopes to the steepest terrain is first to splay the feet to a rising traverse, to kicking steps, to front pointing the crampons. The progression of ice axe technique from the lowest angle slopes to the steepest terrain is to use the ice axe first as a walking stick, then a stake, then to use the front pick as a dagger below the shoulders or above, and finally to swing the pick into the slope over the head. These various techniques may involve questions of differing ice-axe design depending on terrain, and even whether a mountaineer uses one or two ice axes. Anchors for the rope in snow are sometimes unreliable, and include snow stakes, called pickets, deadman devices called flukes which are fashioned from aluminum, or devised from buried objects that might include an ice axe, skis, rocks or other objects. Bollards, which are simply carved out of consolidated snow or ice, also sometimes serve as anchors.

Glaciers

When traveling over glaciers, crevasses pose a grave danger. These giant cracks in the ice are not always visible as snow can be blown and freeze over the top to make a snowbridge. At times snowbridges can be as thin as a few inches. Climbers use a system of ropes to protect themselves from such hazards. Basic gear for glacier travel includes crampons and ice axes. Teams of two to five climbers tie into a rope equally spaced. If a climber begins to fall the other members of the team perform a self-arrest to stop the fall. The other members of the team enact a crevasse rescue to pull the fallen climber from the crevasse.

Ice

Multiple methods are used to safely travel over ice. If the terrain is steep but not vertical, then protection in the form of ice screws can be placed in the ice and attached to the rope by the lead climber. Each climber on the team must clip past the anchor, and the last climber picks up the anchor itself. Occasionally, slinged icicles or bollards are also used. This allows for safety should the entire team be taken off their feet. This technique is known as Simul-climbing and is sometimes also used on steep snow and easy rock.

If the terrain becomes too steep, standard ice climbing techniques are used in which each climber is belayed, moving one at a time.

Mountaineering has become a popular sport throughout the world. In Europe the sport largely originated in the Alps, and is still immensely popular there. Other notable mountain ranges frequented by climbers include the Caucasus, the Pyrenees, Rila mountains, the Tatra mountains and Carpathian Mountains. In North America climbers frequent the Rockies and Sierra Nevada of California, the Cascades of the Pacific Northwest and the high peaks of Alaska. There has been a long tradition of climbers going on expeditions to the Greater Ranges, a term generally used for the Andes and the high peaks of Asia including the Himalaya, Pamirs and Tien Shan. In the past this was often on exploratory trips or to make first ascents. With the advent of cheaper long-haul air travel mountaineering holidays in the Greater Ranges are now undertaken much more frequently and ascents of even Everest and Vinson Massif (the highest mountain in Antarctica) are offered as a "package holiday". Other mountaineering areas of interest include the Southern Alps of New Zealand, the Japanese Alps, the Coast Mountains of British Columbia, the Scottish Highlands, and the mountains of Scandinavia, especially Norway.