Alpine Glossary
155 mountaineering terms explained
🧗 Climbing & Mountaineering
Technical climbing, rope work, and alpine skills.
Aid Climbing
Using equipment placed in the rock to support body weight and make upward progress, as opposed to free climbing.
Alpine Style
Climbing a mountain in a single push without pre-established camps or fixed ropes, carrying all supplies. Contrasted with expedition style.
Belaying
The technique of controlling a rope to catch a falling climber, using friction devices or body position to arrest a …
Bouldering
Climbing short, challenging rock formations without ropes, using crash pads for fall protection. Problems rarely exceed 6 meters.
Crux
The most difficult section of a climbing route or pitch, requiring the highest skill level to overcome.
Dyno
A dynamic move in rock climbing where the climber jumps or lunges explosively to reach a distant hold, momentarily leaving …
Expedition Style
Climbing with a series of pre-stocked camps, fixed ropes, and often supplemental oxygen and porters. The traditional approach for 8000m …
Fixed Rope
A permanently or semi-permanently anchored rope on a mountain route, allowing climbers to ascend and descend without leading.
Free Climbing
Ascending using only hands and feet on the rock, with rope and gear used solely for protection against falls, not …
Free Soloing
Ascending a rock or ice route entirely alone, without any ropes, harnesses, or protective equipment. A fall is almost certainly …
Grade
A rating system indicating the difficulty of a climb. Systems include YDS (USA), French, UIAA, and V-scale (bouldering).
Ice Climbing
Ascending ice formations such as frozen waterfalls, icefalls, and glaciated rock using ice axes and crampons.
Jumar
A mechanical ascending device that grips a fixed rope, allowing a climber to ascend efficiently. Also used as a verb.
Lead Climbing
Climbing while clipping the rope into protection points above, as opposed to top-roping. The leader faces greater fall distances.
Mantling
A technique for surmounting a ledge or flat-topped feature using a push-up motion: first pulling up with hands on the …
Mixed Climbing
Climbing terrain that combines rock and ice, requiring techniques and tools from both disciplines. Graded on the M-scale.
Multi-Pitch
A climbing route that requires multiple rope lengths (pitches) to complete, with belay stations between each pitch.
Onsight
Completing a climbing route on the first attempt with no prior knowledge of the moves and no falls. An onsight …
Pitch
A section of a climbing route between two belay stations, limited by the length of the rope (typically 50-70 meters).
Prusik
A friction knot tied with a loop of cord around a rope that grips when weighted but slides when unweighted, …
Rappelling
Descending a vertical surface by sliding down a fixed rope using a friction device, also known as abseiling.
Redpointing
Successfully completing a pre-practiced rock climbing route in a single push from bottom to top without resting on protection. Redpointing …
Soloing
Climbing alone without a partner, either with self-belay systems (rope solo) or without any protection (free solo).
Stemming
A climbing technique using opposing outward pressure with hands or feet against two surfaces — typically the walls of a …
Traverse
Moving horizontally or diagonally across a face or ridge rather than ascending directly. Can refer to crossing an entire mountain …
Via Ferrata
A protected climbing route with permanent steel cables, rungs, and ladders fixed to the rock, allowing less experienced climbers to …
📜 Culture & History
Mountaineering history, traditions, organizations, and cultural significance.
Alpine Club
A mountaineering organization, specifically referencing the Alpine Club (London, 1857), the world's first such institution, which set standards for the …
Alpinism
The sport and art of climbing high-altitude alpine peaks, traditionally emphasizing skill, self-sufficiency, and style over commercial support. UNESCO inscribed …
Bivouac
An improvised or planned overnight camp in the mountains without a full tent, often using only a bivy sack or …
Cairn Etiquette
The emerging code of practice governing the building and removal of stone cairns in wilderness areas. In Leave No Trace …
Climbing Ethics
The unwritten and written principles governing behavior on mountains, including fair means, style of ascent, environmental responsibility, and treatment of …
Eight-Thousander
Any of the 14 mountains on Earth with summits above 8,000 meters, all located in the Himalayas and Karakoram ranges.
First Ascent
The first successful climb to the summit of a mountain or the first completion of a new route. A defining …
First Winter Ascent
The first successful summit during calendar winter, considered far more challenging due to extreme cold, shorter days, and severe weather.
Fourteen Eight-Thousanders
The complete collection of all mountains over 8,000 m. Completing all 14 is the ultimate mountaineering achievement, first done by …
Golden Age of Alpinism
The period from 1854 to 1865 during which most major Alpine peaks were first climbed, driven by British and European …
Guide
A professional mountaineer who leads clients on climbs, possessing certified skills in navigation, rescue, and technical climbing.
Leave No Trace Peak
A mountain managed under strict environmental protection policies, requiring climbers to carry out all waste including human waste and used …
Mountaineering Club
An organization that promotes climbing, provides training, manages huts, and advocates for mountain access. Historic clubs shaped the sport's development.
Mountaineering Ethics
The broader ethical framework encompassing environmental stewardship, indigenous rights, commercial exploitation concerns, and responsibility toward fellow climbers.
Mountaineering Season
The traditional calendar windows for climbing specific peaks, dictated by weather patterns. Everest pre-monsoon (April–May) and post-monsoon (September–October).
Mountain Hut
A staffed or unstaffed shelter in mountainous terrain providing accommodation, food, and emergency refuge. Hut systems are central to European …
Mountain Rescue Team
A volunteer or professional organization trained to locate and evacuate injured, missing, or overdue climbers and hikers. Mountain rescue teams …
Oxygen Debate
The ongoing ethical discussion about whether using supplemental oxygen on 8000m peaks constitutes a valid ascent or diminishes the achievement.
Permit
Official authorization required to climb certain mountains, issued by national governments. Fees fund conservation, rescue services, and local economies.
Porter
A person hired to carry loads of equipment and supplies during mountain expeditions, essential to large-scale climbs in remote regions.
Prayer Flags
Colorful rectangular cloth flags inscribed with Buddhist mantras, strung on mountain passes and base camps across the Himalayas to spread …
Puja Ceremony
A Buddhist blessing ritual performed at Himalayan base camps before climbing begins, asking the mountain deities for safe passage.
Reinhold Messner
Italian mountaineer (born 1944) who completed the first oxygenless ascent of Everest in 1978 with Peter Habeler and became the …
Seven Summits
The highest mountain on each of the seven continents, a popular mountaineering challenge. Lists vary on whether to include Kosciuszko …
Sherpa
An ethnic group indigenous to the Himalayan region of Nepal, renowned for mountaineering expertise. Also used (controversially) as a job …
Silver Age of Alpinism
The period from 1865 to 1882 following the Golden Age, characterized by the first ascents of more difficult routes and …
Speed Record
The fastest known time for ascending a mountain or completing a route, a growing competitive discipline in modern mountaineering.
Summit Fever
A dangerous psychological compulsion to reach the summit at any cost, overriding rational safety judgments and turnaround decisions.
Trad Climbing
Traditional climbing in which the leader places all protection during the ascent and removes it on the way down, leaving …
Ultra-Prominent Peak
A mountain with a topographic prominence of at least 1,500 meters, making it a significantly independent summit regardless of absolute …
🎒 Equipment & Gear
Clothing, tools, devices, and hardware used in mountaineering.
Abalakov Thread
A V-shaped tunnel drilled through a column of solid ice, through which a loop of cord is threaded to create …
Belay Device
A mechanical friction device used to control the rope while belaying or rappelling. Common types include tube-style (ATC) and assisted-braking …
Bivouac Sack
A lightweight, waterproof emergency shelter that covers a sleeping bag or person, used for unplanned overnight stays. Also called a …
Cam
A spring-loaded camming device (SLCD) placed in rock cracks that expands to create a secure anchor point for climbing protection.
Carabiner
A metal loop with a spring-loaded gate used to connect components in a climbing system, such as rope to harness …
Crampon
A metal frame with downward-pointing spikes attached to boots for traction on ice and hard snow. Essential for glacier travel …
Deadman Anchor
A buried object — snow picket, ice axe, or improvised item — placed horizontally in snow to create an anchor. …
Down Jacket
An insulated jacket filled with goose or duck down, providing exceptional warmth-to-weight ratio for high-altitude mountaineering.
Gaiters
Waterproof coverings worn over boots and lower legs to keep out snow, water, mud, and debris.
GPS Device
A satellite navigation unit that provides precise location coordinates, track recording, and route guidance in the backcountry.
Harness
A system of webbing worn around the waist and legs that connects a climber to the rope, distributing fall forces …
Haul Bag
A large, durable cylindrical bag used to carry supplies and gear up big walls during aid climbing ascents. Haul bags …
Headlamp
A hands-free light worn on the head, essential for alpine starts, night navigation, and cave or tunnel sections.
Helmet
Protective headgear designed to absorb impacts from falling rocks and falls, mandatory on most technical mountain routes.
Ice Axe
A multi-purpose mountaineering tool with a pick, adze, and spike, used for self-arrest, step-cutting, and anchoring on snow and ice.
Ice Screw
A hollow, threaded metal tube screwed into solid ice to create an anchor or running protection on ice climbs and …
Layering System
A clothing strategy using base layer (moisture wicking), mid layer (insulation), and outer layer (weather protection) for thermoregulation.
Nut
A passive metal wedge placed in rock cracks as climbing protection. Also called a chock or stopper.
Portaledge
A deployable hanging tent system that attaches to anchors on a vertical cliff face, allowing climbers to sleep during multi-day …
Quickdraw
Two carabiners connected by a short sewn sling, used to connect the climbing rope to bolts or protection on a …
Rope
The lifeline of climbing, made from nylon kernmantle construction. Dynamic ropes stretch to absorb falls; static ropes are used for …
Snow Picket
An aluminum stake driven into snow at an angle to create an anchor for belaying or rappelling on steep snow …
Stove
A portable cooking device for melting snow and preparing food at altitude. Canister, liquid fuel, and integrated systems each have …
Supplemental Oxygen
Bottled oxygen used above extreme altitudes (typically 7,500m+) to compensate for critically low atmospheric pressure.
Tent
A portable shelter for camping on mountains. Alpine tents are designed for high winds, snow loading, and rapid setup at …
Trekking Poles
Adjustable poles used for balance and to reduce impact on knees during hiking, especially on steep descents.
🏔️ Geography & Geology
Landforms, geological features, and terrain types found in mountain environments.
Alpine Zone
The elevation band above the treeline where trees cannot survive, characterized by low-growing tundra vegetation, exposed rock, and persistent snow. …
Altitude
The vertical distance above a reference point, typically sea level. Often used interchangeably with elevation but technically refers to height …
Arete
A sharp, narrow ridge of rock formed by glacial erosion on two sides. Often a challenging but direct route to …
Bergschrund
A large crevasse or gap that forms at the upper limit of a glacier where moving ice separates from the …
Buttress
A prominent, protruding section of a mountain face, often providing a natural climbing route along its crest.
Cirque
An amphitheater-shaped hollow carved by glacial erosion at the head of a valley, with steep walls on three sides.
Col
A low point or depression on a mountain ridge between two peaks, often used as a pass or route between …
Couloir
A steep, narrow gully on a mountainside, often filled with snow or ice. Couloirs are common climbing routes but prone …
Crevasse
A deep crack or fissure in a glacier, often hidden by snow bridges. One of the most dangerous features on …
Cwm
A Welsh term for a deep, steep-walled basin or hollow carved by glacial erosion, equivalent to a cirque. The word …
Drumlin
An elongated, oval hill of glacial till shaped by the flow of ice, with a blunt upstream end and tapered …
Elevation
The height of a point on the Earth's surface above mean sea level, measured in meters or feet.
Face
A steep, broad side of a mountain, often the most challenging climbing terrain. Named by cardinal direction (e.g., North Face).
False Summit
A point on a mountain that appears to be the summit from below but upon reaching it, the true summit …
Firn
Compacted granular snow that has survived at least one full melt season but has not yet fully compressed into glacial …
Glacial Lake
A lake formed by glacial processes, including cirque lakes (tarns), moraine-dammed lakes, and proglacial lakes at a glacier terminus. Glacial …
Glacier
A persistent body of dense ice that moves under its own weight, carving valleys and shaping mountain landscapes over millennia.
Gorge
A narrow, steep-walled valley or canyon carved by a river through rock. Often found at lower elevations on approach routes.
Hanging Valley
A tributary valley whose floor lies significantly higher than the main valley floor, created when a smaller glacier could not …
Headwall
The steep, vertical, or near-vertical rock or ice wall at the back of a cirque or at the upper end …
Icefall
A chaotic zone of collapsed and fractured glacial ice where a glacier flows over a steep bedrock step. Icefalls are …
Moraine
An accumulation of rocks, sediment, and debris deposited by a glacier. Terminal, lateral, and medial moraines indicate past and present …
Moraine Lake
A lake dammed by a glacial moraine, typically strikingly turquoise due to glacial flour suspended in the water. Moraine lakes …
Nunatak
An isolated rock peak or hill that protrudes above a surrounding ice sheet or glacier. Nunataks serve as refugia for …
Peak
A pointed or prominent top of a mountain, often used interchangeably with summit but technically referring to the shape of …
Pinnacle
A sharply pointed isolated column of rock, ice, or snow, often detached from the main mountain body. Pinnacles may be …
Plateau
An elevated flatland area, often found at high altitudes between mountain ranges. May serve as acclimatization camps.
Proglacial Area
The terrain immediately in front of a retreating glacier, recently exposed by ice melt. Proglacial areas are ecologically dynamic, rapidly …
Prominence
The vertical distance between a summit and the lowest contour line encircling it but containing no higher summit. A key …
Ridge
A long, narrow elevated crest of a mountain, typically with steep sides on both flanks. Ridges connect peaks and are …
Rock Glacier
A slow-moving tongue of rock debris with interstitial ice, moving like a glacier but covered entirely by rocks. Rock glaciers …
Saddle
A broad, gently curved depression between two higher elevations, resembling the shape of a riding saddle. Wider and more gradual …
Scree
A mass of loose rocks and small stones covering a mountain slope, typically below cliffs. Movement across scree requires careful …
Serac
A large tower or block of glacial ice found on steep glaciers, formed where crevasses intersect. Seracs can collapse without …
Subalpine Zone
The elevation band immediately below the alpine zone, above the upper forest limit but sheltered enough to support dwarf trees …
Summit
The highest point of a mountain or hill; the topmost elevation that climbers aim to reach.
Talus
A sloping mass of rock fragments accumulated at the base of a cliff or steep slope, larger than scree.
Tarn
A mountain lake formed in a cirque or hollow carved by glacial activity, typically found at high elevations.
Treeline
The elevation above which trees cannot grow due to harsh conditions. Marks the transition from forest to alpine zone.
Valley
A low-lying area between mountains or hills, often carved by rivers or glaciers, serving as approach routes and base camp …
Valley Glacier
A glacier that flows down a mountain valley, constrained by valley walls on either side. Valley glaciers are the most …
🥾 Hiking & Trekking
Trail terminology, hiking concepts, and trekking practices.
Acclimatization Hike
A hike to higher elevation undertaken specifically to aid the body's adaptation to altitude, following the climb high, sleep low …
Alpine Start
Beginning a climb or hike very early, often between midnight and 4 AM, to take advantage of firm snow, avoid …
Approach
The journey from a road or trailhead to the base of a climb or a high camp, often the first …
Backpacking
Multi-day hiking with all gear, food, and shelter carried in a backpack, camping along the trail.
Base Camp
A staging area at the foot of a mountain from which climbing expeditions are launched, stocked with supplies and used …
Bushwhacking
Traveling through dense vegetation without a defined trail, requiring navigation skills and physical effort.
Cairn
A stack of stones used as a trail marker, especially above treeline or in areas without maintained paths.
Day Hike
A hike completed within a single day without overnight camping, typically under 8 hours of walking.
Elevation Gain
The total vertical distance climbed during a hike, summing all uphill sections regardless of intervening descents.
Gradient
The steepness of a trail or slope, expressed as a percentage or angle. A 10% gradient rises 10 meters over …
High Camp
An advanced camp established at higher elevation on a mountain, used as a staging point for the summit bid.
Hut-to-Hut Trekking
A style of multi-day trekking that uses a network of mountain huts for overnight accommodation, eliminating the need to carry …
Leave No Trace
A set of seven outdoor ethics principles minimizing human impact on wilderness, including packing out waste and staying on trails.
Pass
A navigable route through a mountain range, typically at a col or saddle between peaks. Historically used for trade and …
Portage
Carrying a boat or heavy load overland around an obstacle such as a waterfall, rapids, or impassable terrain. In mountain …
Rest Step
A slow, rhythmic climbing technique where the rear leg is locked straight at the knee for a brief moment with …
Scrambling
Moving over rocky terrain using hands for balance and support, falling between hiking and technical climbing in difficulty.
Section Hike
Completing a long-distance trail in separate trips over time, tackling different sections on each visit.
Summit Bid
The final push from high camp to the summit, typically the most physically demanding and dangerous part of a climb.
Switchback
A zigzag section of trail that ascends a steep slope in a series of back-and-forth turns to reduce gradient.
Thru-Hike
Completing an entire long-distance trail end-to-end in a single continuous journey, typically over weeks or months.
Trail
A marked or established path through wilderness terrain used for hiking, often maintained with signage and cleared obstacles.
Trailhead
The starting point of a hiking trail, typically with parking, signage, and sometimes facilities like restrooms.
Trail Register
A logbook at a trailhead or shelter where hikers record their names, dates, and intended destination. Trail registers assist search-and-rescue …
Trekking
Multi-day hiking in remote or mountainous regions, typically with tea houses or organized camps rather than carrying all supplies.
Trekking Permit
An official document required by some governments to enter protected mountain areas or national parks for trekking purposes. Notable examples …
⚠️ Safety & Survival
Hazards, rescue, medical conditions, and risk management in the mountains.
Acclimatization
The gradual physiological adaptation to decreased oxygen at higher altitudes, typically following a "climb high, sleep low" pattern.
Anchor
A secure attachment point fixed into rock, ice, or snow that the climbing rope is connected to for belay or …
Avalanche
A rapid flow of snow down a slope, triggered by natural causes or human activity. One of the deadliest hazards …
Avalanche Beacon
An electronic transceiver worn by backcountry travelers that transmits a signal for burial location and switches to receive mode for …
Crampon Balling
The dangerous accumulation of wet snow inside crampon frames, reducing the effectiveness of points and making snow slopes slippery. Anti-balling …
Crevasse Fall
An accident in which a climber breaks through a snow bridge and falls into a crevasse. The standard prevention is …
Death Zone
Altitudes above approximately 8,000 meters where oxygen is insufficient to sustain human life for extended periods, causing progressive deterioration.
Dexamethasone
A corticosteroid medication used to treat severe altitude illness (HACE, HAPE) by reducing brain and pulmonary edema. It provides temporary …
Edema
Abnormal accumulation of fluid in body tissues. At altitude, HACE (cerebral) and HAPE (pulmonary) edema are life-threatening medical emergencies.
Emergency Bivouac
An unplanned overnight stay on a mountain due to deteriorating conditions, injury, loss of route, or insufficient daylight. Survival depends …
Exposure
The degree to which a climber is exposed to a fall or the elements. High exposure means a long potential …
Frostbite
Tissue damage caused by freezing of skin and underlying tissues, most common in extremities (fingers, toes, nose, ears) at high …
Gamow Bag
A portable inflatable hyperbaric chamber used in high-altitude emergencies to simulate descent by increasing air pressure around the patient. A …
HACE
High Altitude Cerebral Edema — a severe, life-threatening form of altitude sickness caused by swelling of the brain at extreme …
HAPE
High Altitude Pulmonary Edema — fluid accumulation in the lungs at high altitude, the most common fatal form of altitude …
Helicopter Rescue
Emergency evacuation by helicopter from mountain terrain, often the only viable rescue option at high altitude or in remote locations.
High Altitude Sickness
A group of conditions (AMS, HACE, HAPE) caused by reduced oxygen at altitude, with symptoms ranging from headache and nausea …
Hypothermia
A dangerous drop in core body temperature below 35°C (95°F) caused by prolonged exposure to cold, wind, and moisture.
Lightning Position
An emergency body stance adopted when lightning is imminent on an exposed summit or ridge: crouch low on the balls …
Piton
A metal spike hammered into rock cracks as a climbing anchor or protection point. Pitons leave permanent scarring and are …
Probe
A long, collapsible pole used to locate buried avalanche victims by probing systematically through the snow. An avalanche probe is …
Protection
Any piece of gear (cam, nut, piton, ice screw) placed in the rock or ice to limit fall distance while …
Pulse Oximeter
A small clip-on device that measures blood oxygen saturation (SpO₂) and heart rate. At high altitude, SpO₂ readings below 75–80% …
Risk Management
The systematic process of identifying, assessing, and mitigating hazards in mountaineering through planning, skills, and decision-making.
Rockfall
The descent of loose rocks from a cliff or mountain face, a constant hazard on alpine routes, especially as temperatures …
Rope Team
A group of climbers tied together on a shared rope for glacier travel, allowing partners to arrest a crevasse fall.
Self-Arrest
The technique of stopping an uncontrolled slide on a snow slope using an ice axe driven into the snow, a …
Shovel
An avalanche rescue shovel with a collapsible handle for digging out buried victims. Strategic shoveling — V-conveyor technique — is …
Snow Blindness
A painful temporary eye condition caused by UV overexposure reflected from snow and ice surfaces, equivalent to sunburn of the …
Snow Bridge
A fragile natural arch of snow spanning a crevasse, often concealing the gap below. Snow bridges weaken in warm conditions …
Snow Hole
An emergency or planned shelter excavated into a deep snowbank or drift. Snow insulates extremely well; inside a snow hole, …
Turnaround Time
A predetermined time by which a climbing party must begin descending regardless of proximity to the summit, to ensure safe …
Unplanned Overnight
An enforced overnight stop in the mountains caused by weather deterioration, injury, or disorientation — distinct from a planned bivouac. …
Weather Window
A brief period of favorable weather conditions that allows a safe summit attempt, critical for planning on high mountains.
Whiteout
A weather condition in which snow, cloud, and mist merge to create a uniform white environment with no visible horizon, …
🌦️ Weather & Climate
Meteorology, atmospheric phenomena, and seasonal patterns.
Atmospheric River
A narrow band of concentrated water vapor in the atmosphere that can deliver intense precipitation events to mountain ranges. Atmospheric …
Barometric Pressure
Atmospheric pressure, which decreases with altitude. On Everest's summit, pressure is about one-third of sea level, critically reducing available oxygen.
Blizzard
A severe snowstorm with sustained winds above 56 km/h, reduced visibility below 400m, and lasting at least 3 hours. Can …
Catabatic Wind
A strong, cold wind that flows downslope under gravity as dense cold air drains from high elevations. Katabatic winds can …
Climbing Season
The period when weather and snow conditions are most favorable for ascending a particular mountain. Varies by hemisphere, altitude, and …
Corn Snow
Coarse, granular snow with rounded grains that forms through repeated freeze-thaw cycles. Corn snow provides excellent crampon purchase and predictable …
Dehydration
An excessive loss of body water exacerbated at altitude by increased respiratory rate, low humidity, and physical exertion. Even mild …
Föhn Effect
A warm, dry downslope wind that occurs on the lee side of a mountain range after air has lost moisture …
Freeze-Thaw Cycle
The daily pattern of freezing at night and thawing during the day that loosens rocks, weakens snow bridges, and creates …
Frost
The formation of ice crystals on surfaces when temperatures drop below 0°C. Frost on rock makes holds slippery and increases …
Glacial Wind
A cold downslope wind that flows off glacier surfaces, generated by cold dense air draining into valleys. Similar to katabatic …
Ground Blizzard
A blizzard condition created by strong winds picking up already-fallen snow from the ground without new precipitation falling. Can produce …
Ice Storm
A precipitation event in which rain falls through a subfreezing surface layer, coating terrain and equipment in ice. On mountain …
Jet Stream
A narrow band of strong wind in the upper atmosphere (typically above 7,000m) that can produce extreme wind speeds on …
Katabatic Wind
A downslope wind driven by gravity as cold, dense air flows off elevated terrain such as ice sheets, glaciers, and …
Lapse Rate
The rate at which temperature decreases with altitude, averaging about 6.5°C per 1,000m in standard atmosphere. Steeper rates indicate instability.
Lenticular Cloud
A lens-shaped cloud that forms on the lee side of mountains when stable air flows over a peak. Often a …
Lightning
An electrical discharge in the atmosphere, extremely dangerous on exposed ridges and summits. A leading cause of weather-related deaths in …
Monsoon
A seasonal wind pattern bringing heavy precipitation. In the Himalayas, the summer monsoon (June–September) defines the climbing season.
Mountain Wave
Oscillating air currents that form on the lee side of mountain ranges as stable air flows over a ridge. Mountain …
Orographic Lift
The forced ascent of air as it encounters a mountain barrier, causing cooling, condensation, and precipitation on the windward side.
Permafrost
Ground that remains permanently frozen below the surface in cold mountain regions. Thawing permafrost destabilizes slopes, contributes to rockfall, and …
Polar Vortex
A large area of low pressure and cold air surrounding Earth's poles. When the polar vortex weakens or splits, frigid …
Precipitation
Any form of water — rain, snow, sleet, or hail — falling from the atmosphere. In mountains, precipitation intensity and …
Rain Shadow
An area of reduced rainfall on the lee (downwind) side of a mountain range, caused by orographic lift depleting moisture …
Rime Ice
A white, opaque coating of ice formed when supercooled water droplets in fog or cloud freeze on contact with surfaces. …
Snow Conditions
The state of snow on a mountain, ranging from powder and packed to icy crust and corn snow. Conditions change …
Snowfall Rate
The speed at which snow accumulates, measured in centimeters per hour. High snowfall rates rapidly bury anchors, increase tent snow …
Snowpack
The accumulated layers of snow on a mountain, built up over a season. Snowpack depth, density, and internal structure determine …
Solar Radiation
Electromagnetic energy from the sun, more intense at altitude due to thinner atmosphere and reflective snow surfaces. UV radiation at …
Spindrift
Fine, powdery snow particles blown by wind off ridges and steep faces, often streaming like smoke from summit ridges. Spindrift …
Temperature Inversion
An atmospheric condition where temperature increases with altitude instead of the normal decrease, trapping cold air and pollution in valleys.
Thermal
A column of rising warm air generated by differential heating of the ground surface. In mountains, thermals trigger afternoon cumulus …
Thunderstorm
A localized storm producing thunder, lightning, heavy rain or hail, and strong winds. Afternoon thunderstorm development driven by solar heating …
Virga
Precipitation that falls from clouds but evaporates before reaching the ground. In mountains, virga is common in dry alpine air …
Wind Chill
The perceived decrease in air temperature caused by wind, which accelerates heat loss from exposed skin. Critical factor in frostbite …