Talus is an accumulation of large, angular rock fragments that collects at the base of cliffs and steep slopes, formed by rockfall and freeze-thaw weathering. The blocks are typically big enough to step on individually — from football- to car-sized — distinguishing talus from finer, looser scree. Crossing talus requires careful foot placement, as blocks can shift underfoot.
Scree is an accumulation of small, loose rock fragments and gravel that collects on or at the base of a slope, formed by weathering and rockfall. Smaller and looser than talus, scree shifts and slides underfoot, making uphill travel frustrating and tiring but allowing a controlled sliding descent known as scree skiing. It's a common feature of alpine and mountain terrain.
A snow bridge is a span of snow that forms across the opening of a crevasse, often concealing the gap entirely so it looks like solid ground. Created by wind-deposited and accumulated snow, snow bridges vary enormously in strength — some hold a roped team, others collapse under a single climber. They are a primary glacier-travel hazard, requiring roped travel, probing, and careful assessment to cross safely.
A cornice is an overhanging ledge or mass of snow that forms on the leeward (downwind) edge of a ridge or cliff, built up by wind depositing snow past the edge. Cornices can be huge, are structurally weak, and can break off far back from the apparent edge — making them a serious hazard for travelers on ridges and the slopes below.
A couloir is a steep, narrow gully or chute on a mountainside, typically bounded by rock walls and often filled with snow or ice. Couloirs serve as natural lines of ascent and descent for mountaineers and steep skiers, offering a more direct route up or down a face. But their funnel shape makes them prime channels for rockfall, avalanches, and falling ice, so they carry serious objective hazards.
A col is the lowest point on a ridge between two peaks — a saddle-shaped dip in a mountain ridgeline. Cols are the natural low points where mountaineers and hikers cross from one side of a ridge or massif to the other, often serving as mountain passes and key features on a climbing route. The term, common in mountaineering, is essentially synonymous with a saddle, with 'col' favored in alpine and technical contexts.
Mountaineering boots are stiff, supportive, often insulated boots built for travel on snow, ice, and high mountains, and crucially for use with crampons. They range from single boots for moderate alpine conditions to double and triple boots for extreme cold and altitude, and are rated by stiffness (B1–B3) to match crampon types. Their rigidity supports kicking steps, front-pointing, and carrying heavy loads on technical terrain.
A roped team is a group of climbers connected together by a rope, traveling as a unit so that if one member falls — most importantly into a crevasse on a glacier — the others can arrest the fall and perform a rescue. Standard practice for glacier travel and some exposed terrain, roped-team travel involves proper spacing between climbers, keeping the rope managed, and everyone being ready to drop and self-arrest the instant a teammate breaks through.
A bergschrund is the crevasse that forms at the head of a glacier where the moving glacial ice separates from the stationary ice or rock above it. Often large and located at the top of a glaciated face, the bergschrund is frequently the first major obstacle on a climb — a gap that may require careful crossing via a snow bridge or a technical move. It's distinct from ordinary crevasses lower on the glacier.
A serac is a large block, column, or tower of glacial ice, formed where a glacier fractures as it flows over steep or broken terrain (such as an icefall). Seracs can be the size of houses and are inherently unstable, capable of collapsing without warning regardless of temperature or time of day. Serac fall is one of the most dangerous and unpredictable objective hazards in mountaineering.
