Mountain features

Mountain Features for Mountaineers: 19 Important Terms

If you’ve ever read a mountain route guide, you may have seen some words that confused you. Bergschrund, Col, Dihedral… there are many mountain features and terms that get their name from French, German or Italian – making it difficult to understand. These mountain features are important to learn, as they can help you navigate and avoid major hazards. Here are 19 common mountain features that will help you on the trail.

Table of Contents

Common Mountain Features and Terms

Why are so many mountain features named with European languages? Most of them date back to the Golden age of mountaineering when Englishmen, Frenchmen, Germans, and Italians climbed the Alps and other high peaks around the world. Americans largely adopted the words as mountaineering and rock climbing developed in the Rockies and other major ranges of the west. These nineteen mountain features are a good start for your research.


An arete is a sharp-crested ridge. It is usually the result of two cirque glaciers eroding opposite each other until all that is left is a narrow, pointed ridge. A good example of an Arete is the Sawtooth Traverse that links Mount Bierstadt and Mount Evans (seen right), or the infamous Knife’s Edge ridge on Capitol Peak, the state’s toughest fourteener.


A bergschrund is a giant crevasse found at the upper limit of glacial movement. It forms where moving glacial ice breaks away from ice caps or snowfields above. A bergshrund is often a significant obstacle for mountaineers to overcome, especially in summer months when they become larger and more prominent.


A Chimney is a large crack wide enough to fit a climber’s body, and narrow enough to allow for opposing force to be applied to both walls. They are easier to climb than wider cracks where holds are difficult to reach. Chimney climbing requires special skills, and usually is done using technical climbing gear and a rope, as falls do happen.


A col is a saddle or pass, a low point along a ridge between two summits or points. They are key points for navigation, allowing passage between two mountain basins and access to ridges and spurs for summit access.


A cornice is a large snow deposit on the lee edge of a ridge (the direction that the wind generally blows towards), It usually extends several feet beyond the ridge on which it stands, and can break away if stood on, taking those standing on it with them. Cornices also naturally fall and can spark an avalanche in the right conditions. Be wary of them and give them distance.


A couloir is a steep mountain gully, usually flanked by rugged and rocky cliffs that channel snow within them. Couloirs usually collect snow leading to major avalanches that keep the gully free of trees. In spring, once warm days and cold nights create a hard, icy surface, climbers often climb couloirs using an ice axe and crampons.


A crevasse is a chasm that splits a glacier. As a glacier moves down a valley, it often hits choke points or changes in the bedrock that speed up the movement of ice. This is where it is most likely to stumble upon a crevasse. Whenever there is a risk of a crevasse, it is a good idea to rope up with partners. 


A dihedral is a point where two walls meet in approximately a right-angled curve inside a corner. It is often called an open book, and is climbed using special climbing techniques, where one grabs the corners to use them as holds.


Hoarfrost is ground-level deposits formed when water vapor converts to solid ice or snow. Surface hoar forms on top of the snow, usually following a cold, clear night. This is great for skiing. However, when hoar is buried or forms within the snowpack it can lead to dangerous avalanche risk, often when the snowpack is shallow and unconsolidated.


A massif is a large mountain mass that often includes numerous major summits along a high central ridge. Often, a massif has an unchanged internal structure, rising as a single mass or rock, leading to its consolidated nature. An example is the Blanca Massif in Colorado that includes Blanca Peak, Ellingwood Point, and Little Bear Peak.


A moat is a gap that forms between melting ice or snow and rocks. It can make navigation difficult where large gaps form, with slippery, wet surfaces and sometimes significant exposure. It is especially problematic in late spring and summer.


A moraine is a large mound of rock and debris deposited by a glacier as it moves down a mountain. Lateral moraines form along the sides of a glacier, while a terminal moraine forms as its farthest-reaching point. Moraines that form in the past often trap water and create alpine lakes today.

Objective Hazard

Objective Hazards are any physical risks that are inherently associated with the route and cannot easily be mitigated. This includes significant rockfall, exposure, high altitude, and localized variable weather conditions.


An off-width is a crack that is too wide for a hand jam technique but is too narrow for chimney climbing. They can therefore be a major climbing obstacle for mountaineers.


Scree is a loose slope of small rock fragments, similar to pebbles or gravel. They slide easily, leading to the related concept of ‘scree surfing.’ Descents on scree are especially dangerous, as a fall can leave you sliding down the mountain. They’re also difficult to ascend, though not as dangerous as descending.


A serac is a large tower of ice, formed by large crevasses that eventually totally separate. They are extremely unstable, collapsing without warning and causing significant injuries or death when they do. K2 is home to some of the most intimidating seracs on Earth, guarding the steep crux of the route to the summit.


A spur is a large ridge that leads away from a higher massif or mountain. They are often used to climb peaks, especially in glaciated areas where valleys are buried in ice.


Talus is a slope with larger rocks and boulders that can be stepped from one to another – larger than scree. While it is easier to climb as it is more stable, it is still time-consuming to cross compared to a snow climb or hiking trail. 


Verglas is a type of slick ice that forms on rocks and boulders from trickling water that freezes overnight. It is often clear and hard to see, a significant hazard when doing exposed class 3 or 4 scrambles during the spring and early summer.

Wind Slab

A wind slab is a condensed, hard slab of snow that forms on steep mountain slopes following windstorms. They are a major avalanche risk, often breaking down to weaker layers deeper down, and bringing down massive slides. Avoid avalanche-prone slopes after wind events, and learn how to recognize wind-loaded slopes.

Common Mountain Features: Now You Know!

It is helpful to know these mountain features and terms very well. They can help you navigate stark alpine environments with few major landmarks. Others, like crevasses or wind slabs, are potential hazards on a mountain. Understanding which mountain features are safe and which are hazards will help you climb more safely on the peaks. To learn more about major mountain features, I recommend searching on Wikipedia, or getting an Intro Geology textbook. They have a wealth of information on mountain features. Safe travels on the trail!

Alex Derr, Founder of The Next Summit

Alex Derr is an Eagle Scout, climber, and environmental policy expert located in Denver, Colorado. He created The Next Summit to help others stay safe exploring the mountains and advocate to preserve the peaks for the future. Follow him on Linkedin or Twitter or click here to contact him.

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