Hazard Assessment

A spectrum of illness from inadequate acclimatization, ranging from a mild headache (AMS) to fluid building in the brain (HACE) or lungs (HAPE), either of which can be fatal without prompt descent.

A storm hazard that rises sharply on exposed ridges and summits, where afternoon convective buildup is the usual trigger. The standard defense is an early start and being off high terrain before storms build.

A hazard you're exposed to just by being in a place, regardless of skill or judgment, like rockfall, icefall, or a serac collapse. Distinct from subjective hazards, which come down to decisions a party makes.

Rock dislodged by freeze-thaw, wind, animals, or other climbers, falling onto terrain below. Risk rises sharply in the afternoon as the day's warmth melts the ice holding loose rock in place.

A danger created by a party's own decisions and skill, rather than the terrain itself, such as poor route-finding, fatigue, or pushing on past a safe turnaround time. The counterpart to objective hazard.

A loss of visual contrast between snow, sky, and terrain, usually from low cloud or fog over a snowfield, making it easy to lose all sense of slope angle, distance, or direction.