A bivouac, or bivy, is a minimalist overnight stop on a mountain, often unplanned, using little or no shelter beyond a bivy sack or improvised cover. Alpinists deliberately bivy to climb light and fast on long routes, while an unplanned 'forced bivy' is an emergency when a party is caught out overnight.
Glissading is descending a snow slope quickly and deliberately by sliding — on your feet (standing glissade) or seated — using an ice axe to control speed and stop. It is a fast, fun way down, but glissading with crampons on is dangerous (catching a point can break a leg), and runout hazards must be checked first.
A summit bid (or summit push) is the attempt to reach the top of a mountain, typically the final, committing stage of an expedition launched from a high camp. Summit bids are timed for a weather window and good conditions, and require turnaround discipline — committing to descend if the climb runs late or conditions deteriorate.
An alpine start is beginning a climb very early — often well before dawn — to take advantage of cold, stable conditions and to leave a safety margin for the descent. Frozen snow is firmer and safer in the early hours, rockfall and avalanche risk is lower, and an early start means finishing before afternoon storms.
A moraine is a ridge or deposit of rock and debris left behind by a glacier. Lateral moraines run along a glacier's sides and terminal moraines mark its furthest advance. Mountaineers often follow or cross moraines to access glaciers, where the loose, rubbly ground can be unstable and tiring.
A snow bridge is a span of snow that forms over a crevasse, sometimes hiding it completely. Snow bridges can be strong enough to cross or thin enough to collapse under a climber, which is why glacier travelers rope up, probe suspect bridges, and cross them carefully or avoid them.
A cornice is an overhanging lip of wind-blown snow that builds out horizontally from a ridge crest, like a frozen wave. Cornices can collapse under a climber's weight or break off naturally, so mountaineers stay well back from the edge and treat the slope below as avalanche-prone.
A couloir is a steep, narrow gully on a mountainside, often filled with snow or ice, that provides a natural line of ascent or descent. Couloirs are classic alpine and ski-mountaineering routes, but they channel rockfall, avalanches, and meltwater, so timing and hazard awareness are critical.
Mountaineering boots are stiff, insulated, crampon-compatible boots built for snow, ice, and high-altitude climbing. Their rigid soles support precise cramponing and kicking steps, while insulation — and on the warmest models, double-boot construction — protects against frostbite. They're categorized by stiffness and warmth to match the objective.
A bergschrund is the crevasse that forms at the head of a glacier where the moving glacial ice pulls away from the stationary ice or rock above. Often deep and bridged by snow, the bergschrund is a classic obstacle and crux at the start of many alpine climbs, sometimes requiring a tricky crossing.