C: Conducted - Events conducted by a non-Sierra Club entity

O: Ordinary - Uncomplicated outings (i.e. city walks, bike rides, trail hikes, backpacking) which may involve simple off trail hiking not requiring navigation skills. Climbing level: 'Class 1' terrain.

I: Intermediate - Includes outings that involve cross-country travel where navigation is necessary. Rougher ground than 'O' outings may be traversed, and the use of hands for balance may be necessary. Includes outings t

M: Moderate - Includes moderate level climbing: 'Class 3' terrain. On rock, the hands are used for climbing. Some participants may want a safety belay. On snow, safety dictates the use of ice axes and the ability to se

E: Extreme - More exposed than an M outing. Climbing on 'Class 4' terrain. Rock climbs will use a rope for all in the party. On snow, steeper terrain than M outings is permissible, and safety dictates the use of crampo

T: Technical - Technical outings requiring specialized skills as identified in the sponsoring group's safety policy.