SierraDescents Glossary of Mountaineering Terms

from Abseil to the Zipper Effect


The European (originally German) term for Rappel.

Alpine Start

Do you like to suffer? Have I got an idea for you: climb all night in darkness. Climbers call this an Alpine start, which basically means "hideously early."

Why do they do it? Safety, mostly. Things soften in the daylight, making climbing harder, slower, and more dangerous. Avalanche and rockfall danger increases. So by climbing as much of your route as you can in the frozen air of darkness, you're actually reducing your risk. Theoretically.

Me I much prefer staying in bed.

One inarguable perk of alpine starts is you get to watch the sun rise after hours staring at the tiny circle of light from your headlamp. These ethereal moments can be magic indeed, perhaps even justifying setting the alarm so early.



Any solid, fixed point of attachment with which climbers connect themselves, usually via rope, to the Earth to prevent a lengthy fall. Ie, a tree, a piton, or an ice bollard.

As you'd expect, Anchors vary greatly in their degree of reliability, with a healthy, mature, firmly-rooted tree ranking high on the list, and old, rusty climbing hardwear placed by previous persons unknown ranking near the very bottom of the heap.


The broad, triangular (or "apron"-shaped) region immediately beneath a Chute or Couloir, formed by the gradual erosion of rock and snow above.


Which direction (north/south/east/west) way a mountain's slope faces. A south aspect faces south (ie, toward the sun); north aspects (in the Northern Hemisphere) are notoriously shady.

In North America, northeast aspects tend to be the most dangerous in terms of avalanches because our winds blow prevailingly from the southwest—the opposite direction—creating wind-loaded and thus inherently unstable snowpacks on NE aspects.


Were it not for avalanches, goes the saying, backcountry skiing would be a perfect sport.

An avalanche is a tumbling mass of snow and/or ice which occurs whenever the snow's weight, drawn by gravity, overcomes the frictional and cohensional forces holding it in place on an angled slope.

Avalanches are easily the most vexing of hazzards facing winter mountaineers, as it can be exceedingly difficult, if not impossible, to accurately gauge the threat they pose under any given set of conditions.

The only reliable rule of thumb with which one can safely avoid Avalanches is to avoid all snowy regions in winter.

Since that is rarely an acceptible strategy for winter enthusiasts, mountaineers generally employ a variety of tacticts for safe travel in Avalanche country, including the least effective—denial—as well as education (effectiveness: mixed), evaluation of snowpack (challenging), and careful route selection (better).


To secure a climber, usually via a rope tied either to another climber or a fixed Anchor, thus lessening the risk of injury in the event of a fall.


A crevasse that forms between a glacier and the permanent snow pack above. As the glacier gradually creeps downward, it pulls away from the snowpack creating the crevasse.


Is it a chute or is it a couloir? Perhaps not quite synonymous terms referring to the steep, narrow, passages that form in cliff bands as they gradually erode.

Chutes and Couloirs form essential passageways for ascending climbers and descending skiers, as they are inevitably of lesser angle than the vertical walls of rock that surround them.

See also: gully


Thank the French for this one: difficulty rating assigned to notable ski descents of the past, such as the Gervasutti Couloir, now considered easy or "Classic".

While Classic is thus synonymous with 'easy', one should keep in mind the essential element of style involved in calling a 45° thousand vertical meter couloir facile.


French term for chute (more or less).

Americans are perhaps best advised to use 'chute' instead of couloir, as it saves the difficulty of attempting to pronounce the word correctly—"COOL-WAH."


A fracture, split, or gap in a glacier's ice.

Crevasses tend to form perpendicular to tension in the ice and are thus most often seen as horizontal gashes across the face of a glacier, usually concentrated as points of convexity.M

Often hidden by thin layers of snow at their tops, Crevasses pose a significant threat to passing climbers, so much so that Roping Up is considered standard practice when traveling wherever Crevasses are possible.

Depth Hoar

Also known as TG (temperature gradient) Snow, now generally referred to as faceted snow, the bane of backcountry skiers—a weak snow layer comprised of crystals with relatively little adhesion to each other, hidden within seasonal snowpack—and which greatly increase Avalanche risk.

Depth hoar commonly forms in early winter, when a scant few inches of snow sit upon bare ground, and act as a thin insulating layer between the ground and the much colder air above.

This large temperature gradient, often exceeding 40° or 50° F, leads to destructive metamorphosis of the snow crystals, preventing the snow from consolidating into a cohesive mass.

Once formed, depth hoar can linger throughout the winter, creating a persistent point of snowpack weakness.

Depth hoar is more prevalent in the Continental Rockies (especially Colorado's San Juan range) than in the Pacific Coast ranges (though changes in global weather patterns may be invalidating this generalization).


Element of advanced skiing technique in which the skier rapidly flexes the legs, bringing the feet and skis upward so quickly that the body is temporarily "unweighted"—essentially in a state of mini-free fall—and the skis are temporarily made more easy to pivot or turn.

All ski technique depends to some extent on unweighting the skis in order to reduce the friction between skis and ground. Down-Unweighting is a more advanced technique than the ubiquitous Up-Unweighting, and is especially suited for turning on unusually steep slopes, such as might be encountered by Extreme Skiers.

See also: up-unweighting

Extreme Skiing

"Extreme" initially refereed to the transcendent descents of European ski mountaineers, before being seized upon by the American public (and various marketers) and thus thoroughly debased.

Extreme skiing in America perhaps began with Chris Landry's remarkable (and remarkably dangerous) 1970's descent of the east face of Colorado's Pyramid Peak—a feat that went unrepeated for nearly thirty years.

Subsequently, the word extreme was co-opted by the freestylists and airmen of Squaw Valley, whose big-air jumps off the Palisades headwall (notably: Scott Schmidt) were visually spectacular, if not necessarily life threatening.

Fed up with the marketing and hyperboli associated with the term, skiers began seeking other ways to label their exploits (such as Trevor Peterson's somewhat-in-jest 'Severe Skiing'). Today, however, the word seems to have regained a bit of its respectibility, as Americans are now undeniably skiing technical descents wherever they find them.


Can refer to a variety of concepts: Exposure to the weather, to vertical terrain (and the threat of a fall), or to the sun.

Climbers speak of exposure as the both the feeling of intense vertigo that accompanies standing on the edge of a large precipice (see gripped) as well as the actual physical risk associated. Ie: I felt exposed as I traversed the knife-edge arete.

Similary, to be exposed is literally to be in a precarious position, in which the terrain is steep enough that arresting a fall would be difficult, dangerous, or even impossible.

Rescuers may speak of climbers being overcome by exposure: ie, the cooling of the body due to low temperatures and/or wind.


Also: faceted snow. Faceted snow crystals refer broadly to snow which has undergone destructive metamorphosis, in which the crystals enlarge and become less and less bonded to each other.

Faceted snow is often compared to sugar for its loose, uncompactable consistency. In the backcountry, the presence of faceted snow indicates a weak layer in the snowpack which may give rise to avalanches.

Fall Line

From any given point, the most direct path down the mountain.

It can be helpful to visualize the fall line as the path a ball would take if you released it from wherever you're standing, or perhaps more vividly, the path water would flow down.

Experienced skiers tend to innately develop a feel for the fall line, which is a valuable skill for mountaineers of all disciplines.

French Technique

French Technique

Also known as Flat-Footing, an efficient means of ascending moderate-angled snowfields in which the feet are kept flat across the hill (such as while traversing), even while climbing.

Climbers ascending in this manner have an odd, sidewinder-like gait, as they place one foot sideways above the other, over and over again.

The reward of this seemingly-awkward motion, however, is efficiency. French Technique significantly minimizes strain on the lower leg muscles compared to German or Front-Pointing technique.


One (big) step beyond a permanent snow pack, glaciers are formed by many years of snow accumulating and eventually solidifying into ice.

How do you know if you're got a glacier versus just a big pile of snow? Glaciers are so heavy they actually flow—slowly—down the hill, like literal rivers of ice (this is why, incidentally, bergschrunds form between cliffs and glaciers).

If it moves inexorably downward, it's a glacier. If not: big pile of snow.

Glaciers can be massive, and are in a state of continual flux, either expanding or shrinking. Glaciers feature a variety of features, such as seracs and crevasses, which significantly add to the challenges of safe travel

See also: Glaciers of California by Bill Guyton.


Literally, to slide down a snowfield on one's feet, belly, or bottom, usually while using an ice axe as a brake. Glissades can be a valuable means of rapidly descending a snowy slope; however, the technique is not without peril, and should not be considered unless the slope angle is moderate and the runout (in the event of uncontrolled descent) is safe


According to Lou Dawson, a derivative of the French verb glisser, meaning "to slide"—incidentally the root of glissade or the musician's glissando.

Used as an inclusive term to incorporate every and all means of sliding down a snow-covered slope on some sort of edged board. Perhaps best enjoyed in actuality rather than debated symantically.


Euro term for ski crampons. Did you know in the Sierra ski crampons are illegal? The police will actually arrest you if they catch you using them.

I myself barely evaded capture once while skiing California's most fearsome mountain, Cuyamaca Peak. They'll never take me alive.


When glaciers travel over steep ground, their surfaces become chaotically fractured with Crevasses and Seracs.

Such regions are best avoided by casual mountaineers, though experienced Ice Climbers may seek out Icefalls as ideal places to practice their craft.

See also: Glacier

Jump Turn

Ski technique in which the skier jumps from a standstill/traverse position, pivots in the air, and lands facing (hopefully) in the opposite direction.

To some extent, all turns incorporate this up-and-down motion (see Up-Unweighting). More vigourous or exaggerated Jump Turns can be useful when the snow features a breakable crust or otherwise difficult conditions.

Skiers may resort to jump turns (sometimes called Kick Turns) on very steep terrain, though in fact the Jump or Hop turn is actually quite ill suited for it.

Kick Turn

(1) the same as the Jump Turn, as in the famous ski run KT22 at Squaw Valley, which reportedly was descended first via 22 Kick Turns.

(2) Perhaps more commonly, a sequence of moves used to reverse direction while positioned across the hill, at a standstill on a steep slope.

In this case, skiers essentially flip one ski across the hill, such that the legs are briefly pointed in opposite directions, before following with the other leg.

Kick Turns in this manner are either an invaluable means to rotate one's self 180 degrees without signficantly changing one's position, or else a spectacularly effective way to initiate a tumble down the hill.


Technically, a large, cohesive block or unit of the Earth's crust that has been moved as an entire section. In Mountaineering terms, the relatively contiguous portion of a mountain distinguishing it from its neighbors or surrounding range.


Often immense bermed piles of debris at the base of a glacier (or where a glacier once stood), formed as the glacier carries and/or pushes boulders, rocks, and soil during its downward journey.

Moraines offer an intriguing glimpse at the historical terminus of a glacier—ie, the point where the ice melted.


Officially the permanent, consolidated snow pack above (and separate from) a glacier, but now commonly used as a synonym for consolidated snow, or consolidated spring corn, or perhaps any kind of snow, depending on who's talking.


Metal stake hammered into cracks in rock to create an anchor for Belay.

Use of Pitons (as well as bolts) did fall out of favor for a time, as they do damage rock; however the advent of sport climbing has caused a reassessment of fixed protection ethics, so feel free to bold away.



Means of descending steep terrain in which climber descends along an anchored rope, typically via harness and friction device.

Statistically speaking, it should be noted that rappelling is among climbing's most dangerous activities, as one depends entirely on the reliability of the rope/harness/anchor system.


Water frozen (or 'plastered') directly to an object due to specific combination of wind, humidity, and temperature.

Roping Up

When climbers attach themselves to each other—or to anchors—via rope.

The roping up point often occurs at a fixed point along the climb, such as when Class 3 scrambling becomes Class 4 (or higher) rock climbing, or when a glaciated section of the route is encountered.

Self Arrest

Fundamental ice and snow climbing technique in which an ice axe (typically) is used to slow and hopefully halt an unplanned fall or slide on a snowfield.

Self-arrest has its limits; as the slope steepens (and consequences grow more dire), the technique unfortunately loses its effectiveness, particularly in icy conditions.


Technique in which the ice axe's shaft is plunged into the snow to serve as a belay anchor in the event of a fall.

Learn this one well: when successful, self-belay is easily the preferred choice over self-arrest, as it (potentially) arrests a fall before the climber gains any downward momentum.

The key to successfully executing a self belay is quick, decisive action—immediately thrust the axe into the snow, kick in your crampons if possible, and otherwise do everything in your power to arrest yourself.

Note that an ax or in fact any other mountaineering tool is not required. Once while climbing as a kid in the Wasatch I slipped and began sliding on loose ground immediately over a very tall cliff.

I immediately grabbed a nearby tree branch, which stopped me quite nicely. Thank you very much, unknown Wasatch tree!


Large, unstable towers of ice seen on glaciers, especially in ice fall regions. For climbers, really, really nasty stuff.

Seracs are formed as glaciers creep over vertical terrain—cracking and shattering the ice. Large Seracs often topple unpredicatably, posing a formidable threat to climbers passing below.

Quite possibly the most deadly threat on many glaciers (though of course not the only one).

Ski Crampons

Ski Crampons

Metal-toothed brackets that attach either to ski bindings or directly to the skis.

Like regular Crampons, Ski Crampons bite down into snow and ice, enabling greater security while ascending or especially while traversing across hard snow.


SKi-length strips featuring nylon plush on one side and a gluey adhesive on the other.

Skins are fixed to the bottom of the ski, and provide friction against the snow, enabling skiers to ascend uphill on skis via some sort of touring binding.

Skinning is a remarkably efficient means of travel up a snowy slope, and has become the standard means of ascent for backcountry skiers.


Steep, loose piles of rock, formed by the constant process of erosion, and ubiquitous to the mountains.

While not technical challenging, climbing Talus can be exhausting—and dangerous as well, due to the possibility of landslides


Variation of skiing in which the heel remains free, rather than locked as in Alpine or Randonee. Devotees of this style of skiing employ a Telemark Turn, and should be teased at every opportunity as followers of an inferior religion


The act of moving horizontally across an angled face (ie, not gaining or losing altitude), on skis or otherwise. Traversing can be more tedious and difficult than actually climbing a face, and for this reason, climbers may wish to choose their routes so as to avoid long traverses


All ski technique depends to some extent on unweighting the skis in order to turn or pivot them. When up-unweighting, the skier bounces or hops upward in order to temporarily reducing the friction between the skis and the hill. See also: down-unweighting


Thin, clear coating of ice over rock. Verglass can turn an otherwise easy climb into a formidable challenge

Wet-Snow Avalanche

A more predictable & much slower avalanche than the slab variety, typically occurring later in the day, when the sun has warmed/melted the snow pack. It can be tempting to dismiss wet snow avalanches as trivial threats, but they can become quite large and thus threatening


Blizzard or cloud conditions in which the horizon is indistinguishable from the featureless white sky. In extreme forms, White-outs can make it impossible to determine which way is up or down, or even if one is moving or stationary, and thus obviously pose an immediate danger to backcountry travelers


Embedded rock fragment not belonging to the indigenous surrounding rock. The best I could find for a word that begins with "X".

Yosemite Decimal System

A subjective but widely accepted numerical system used to rate difficulty of rock climbing routes. Hiking and Climbing Routes are somewhat ambiguously rated as follows:

Of special concern to hikers and scramblers is the disagreement surrounding the Class 3-4 ratings. Different guidebook authors use different definitions.

For an interesting discussion of the YDS, see

*NOTE: SierraDescents proposes the following modification: the presence of exposure should require a mandatory Class 4 or higher rating, regardless of climbing difficulty. Additionally, Class 4 climbing should always be trivial—that is, an average fit adult should be able to climb a Class 4 section without assistance (though they will likely want a rope).

Zipper Effect

the Zipper Effect

Nasty phenomenon in which protection pieces are pulled out one by one when a climber falls, due to the sideways, upwards, or otherwise unanticipated direction of force being exerted on the protection, rather than the expected downward direction.

The zipper effect can be minimized by properly equalizing protection.

Andy Lewicky is the author and creator of SierraDescents