Activities and Levels

Requires basic knowledge of easy mountaineering techniques:
easy level, climbing with little or no belaying, well protected, may involved crevasses but straightforward glaciers

Requires mastering mountaineering techniques:
at a level of minimal difficulty: moderate climbing, usually requires some belaying, possible rappel on descent, exposed scrambling, crevassed glaciers

to a fairly difficult level: belayed climbing, in addition to large amounts of exposed but easy to navigate terrain. A wide range of protective systems are needed.
Walking as an autonomous rope party or with guide.

Requires more active involvement. Must have a good control of mountaineering techniques:
from a fairly difficult level: belayed climbing, in addition to large amounts of exposed but easy to navigate terrain. A wide range of protective systems are needed

to a difficult level: climbing at a fairly high standard. Difficult routes either involve thousands of feet of moderate climbing or a shorter but harder route.