Tag: mountain/alpine

Ablation is the reduction of a glacier's snow and ice through melting, evaporation, sublimation, and calving. It occurs at every surface, all at once, though at different speeds. The ablation zone is located at the spot where more ice is lost than winter snow accumulation can replace.

 The upper portion of a glacier where snowfall exceeds melt, and where fresh snow compresses into firn and eventually into glacial ice. The accumulation zone is where a glacier is born — it is the account into which deposits are made. Below it, in the ablation zone, the withdrawals happen.

 A wind that flows uphill during the day, caused by solar heating of a mountain slope. As the slope warms, the air in contact with it becomes lighter than the surrounding air and rises. The gentlest and most ordinary of mountain winds — a daily breathing of the valleys.

 A narrow, acute ridge of rock formed where two planes of a cliff intersect, like the corner edge of a building. Can be blunt and rounded or knife-sharp.

 A mass of snow, ice, and debris sliding rapidly down a mountainside. The word is clinical but the thing itself is not — an avalanche can move at 200 miles per hour and bury everything in its path in minutes.

A broad, gently sloping apron of alluvium and debris fanning out from the base of a mountain range into a desert basin, formed by the merging of multiple alluvial fans. The bajada is the transition zone between mountain and flat — neither steep nor level, built grain by grain from the sediment the mountains shed. Desert cities from Tucson to Tehran are built on bajadas.

A cloud that streams from only one side of a mountain summit, like a flag. Formed not by moisture carried over the peak but by air drawn up the lee side into lower pressure. Everest has one. Flat ridges do not.

A landscape of parallel mountain ranges separated by flat desert valleys — the defining topography of the interior American West from eastern California to central Utah, and from southern Idaho to northern Mexico. The ranges are horsts; the valleys are grabens. The earth's crust is stretching, pulling apart, and the landscape is cracking into long, north-south strips of mountain and basin, mountain and basin, repeated for a thousand miles. The phrase names both the landform and the geological province.

 A seasonal hot, dry wind that blows from the high interior plateau of southern Africa down to the coast, mainly in winter. It can raise coastal temperatures dramatically and is the South African equivalent of a foehn.

 A deep crevasse that forms where a glacier pulls away from the headwall of a mountain. Often the last major obstacle before a summit push, and sometimes impassable.

A day of perfect weather — cloudless sky, calm wind, clean visibility. The kind of day that makes you abandon whatever you were planning to do indoors.

 A cold, dry, fierce wind that blows from the northeast down the Dinaric Alps to the Adriatic coast, mainly in winter. It arrives in violent gusts and can sustain gale force for days, making the eastern Adriatic one of the windiest coastlines in Europe.

Your own shadow projected onto mist or cloud below you, enormously magnified, ringed by a circular rainbow called a glory. You are the giant.

A steep-sided, flat-topped hill smaller and narrower than a mesa — an isolated remnant of resistant rock standing alone in an eroded landscape. A butte is a mesa that has lost most of its surface area to erosion, its cliffs steeper than its top is wide. Monument Valley's iconic silhouettes are buttes. The word implies solitude — a butte stands alone.

A prominent projection of rock from the face of a mountain or cliff — a rib, a pillar, a flying wall of stone standing proud of the main face. Buttresses are some of the most sought-after climbing objectives: they catch light, shed water, and offer continuous lines of ascent that feel like climbing the mountain's spine. The word comes from architecture, but the mountain's buttresses came first.

 A mound of stacked stones, built by human hands for any of a dozen purposes — marking a trail, commemorating the dead, indicating a summit, claiming territory, honoring a place, or simply because stacking stones is one of the oldest human impulses. Cairns range from knee-high trail markers to massive Bronze Age burial mounds. They are found on every continent where there are rocks and people.

A large, roughly circular depression formed by the collapse of a volcano's summit after an eruption empties or partially empties the magma chamber beneath it. The mountain falls into the void it created. Calderas can be miles across and thousands of feet deep. Crater Lake in Oregon fills a caldera. Yellowstone sits inside one. The word names the absence — not the mountain but the hole where the mountain was.

 A terraced hill — an isolated, often volcanic hill whose slopes have been shaped with stone retaining walls and platforms by pre-Hispanic peoples of the Sonoran Desert and northwest Mexico. The terraces served as house platforms, garden plots, water-catchment surfaces, and possibly defensive positions. Hundreds of these sites exist from Durango to southern Arizona, some over 3,000 years old, representing one of the longest-lived architectural traditions in North America.

The winter ice-path formed by a frozen river in Zanskar, Indian Himalayas — the only route in or out of the valley during the winter months. Parties undertaking the chadar are led by experienced ice-pilots who can tell where the dangers lie. In its deeper pools, the ice is blue and lucid.

 A warm, dry wind that descends the eastern slopes of the Rocky Mountains, most commonly in winter and early spring. Its arrival is sudden and dramatic — temperatures can rise 30 or 40 degrees Fahrenheit in hours, and snow that took weeks to accumulate can vanish in a day. Called "the snow eater."

 A bowl-shaped mountain basin carved by glacial erosion, steep-walled on three sides and open on the fourth, often holding a lake at its floor. An amphitheater made by ice over millennia.

Loose sediment that has accumulated at the base of a slope through the action of gravity — not carried by water or wind but simply fallen, slid, or crept downhill under its own weight. Colluvium is the material that gathers at the foot of a cliff, at the toe of a landslide, or along the lower edge of any steep terrain. It is unsorted, angular, and often unstable — a slope's debris pile, still in the process of arriving.

A long, continuous chain of mountain ranges — a system of mountains, not a single range but a connected series of ranges running parallel or branching from a common spine. The Andes are a cordillera; the American Cordillera runs from Alaska to Patagonia. The word implies scale and continuity — not one mountain, not one range, but the whole linked backbone.

 An overhanging mass of wind-deposited snow at the edge of a ridge or peak. Cornices build outward from the windward side, creating a false edge — what looks like solid ground may be an unsupported shelf of snow over empty air.

 A steep mountain gully, often filled with snow or ice, that channels everything falling from above — rockfall, avalanche debris, spindrift. A natural chute, beautiful and dangerous in equal measure.

 An open crack in the surface of a glacier, formed when the ice moves over uneven terrain or flows at different speeds in different places, and the brittle upper layer fractures under the stress. Crevasses can be 150 feet deep, 60 feet wide, and hidden beneath a thin snow bridge that looks solid until you step on it. They are the constant, invisible danger of glacier travel.

The Welsh word for a cirque — a bowl-shaped, glacially carved mountain basin with steep headwalls. Cwm is used internationally in mountaineering: the Western Cwm of Everest, the valley between the Lhotse face and the West Ridge, is the most famous application. The word is one of the few in English with no standard vowel.

Trees dwarfed by wind, cold, or exposure at altitude or high latitude. Centuries old, waist-high. The broader category that includes tuckamore and krummholz — any tree that has spent its entire life being told by the weather to stay low.

The degree to which a site is open to weather — wind, sun, precipitation, temperature extremes. A south-facing slope has different exposure than a north-facing one. A ridge has more exposure than a hollow. In mountaineering, exposure also means the consequence of a fall — a ledge with thousands of feet of air below it is "exposed" regardless of how wide it is.

A steep slope or cliff created by vertical displacement along a fault during an earthquake — one side of the fracture lifted or dropped relative to the other, leaving a fresh, raw face of exposed earth or rock. Fault scarps are the most dramatic visible evidence of seismic activity. In the Basin and Range of Nevada and Utah, the mountain fronts are fault scarps — the valleys dropped while the ranges rose, and the abrupt transition between flat basin and steep mountain is the fault's signature.

 Compacted granular snow that has survived at least one summer's melt cycle without becoming ice. The intermediate stage between fresh snow and glacial ice — dense, rounded crystals bonded together, older than a season but younger than a glacier.

A long, narrow, deep inlet of the sea between steep cliffs, carved by a glacier that once flowed to the coast and scoured a valley well below sea level. When the glacier retreated and the sea flooded in, the valley became a fjord. Fjords are among the most dramatic coastal landforms on earth — sheer walls rising thousands of feet from dark water hundreds of fathoms deep. Norway's Sognefjord is over 4,000 feet deep and 125 miles long.

A triangular slab of rock tilted steeply against a mountainside, its broad base at the bottom and its point at the top — resembling the shape of an old flat iron used for pressing clothes. Flatirons form when a resistant layer of rock (usually sandstone) is tilted steeply by tectonic uplift and then eroded into isolated triangular remnants. The Flatirons above Boulder, Colorado, are the iconic example.

 A warm, dry wind that occurs on the leeward side of a mountain range. As air rises on the windward side, it cools and drops its moisture as rain or snow. Cresting the ridge, the now-dry air descends on the other side, compressing and heating as it drops — arriving in the valley below warmer and drier than when it started. The foehn is the archetype; all similar winds worldwide are classified as "foehn-type."

A vent in the earth's surface from which volcanic gases and steam escape — a hole in the ground that breathes hot, sulfurous air. Fumaroles are found on active volcanoes, in geothermal fields, and near hot springs, marking the places where the planet's internal heat reaches the surface. The gases — mostly water vapor, carbon dioxide, and hydrogen sulfide — give fumaroles their distinctive rotten-egg smell. They hiss, whistle, and roar, depending on pressure.

A rock tower or pinnacle on a mountain ridge that blocks progress along the crest, forcing climbers to detour around or over it. Gendarmes guard the ridge the way policemen guard a street — you don't pass without dealing with them.

A series of concentric colored rings that appear around the shadow of your head on fog or cloud, caused by light backscattering through water droplets. Seen from mountaintops, aircraft, and alongside the Brocken spectre. The glory is always centered on your own shadow — each person sees their own.

The opposite of a bluebird day — overcast, flat light, low clouds, the sky the color of old concrete. Not necessarily stormy, just the absence of anything good happening overhead.

A narrow, steep-sided ravine, especially one carved by intermittent water in mountainous terrain — smaller than a canyon, rougher than a valley, and usually dry. The word is quintessentially Western American: mining camps, ghost towns, and place names across the mountain West sit in gulches.

The source area of a river — the springs, snowmelt, seeps, and tiny tributaries that gather at the highest elevations of a watershed and become, eventually, the river itself. The headwaters are the beginning, the place where water first decides to go somewhere.

A fierce, cold, northeasterly wind that blows down the western escarpment of Cross Fell in Cumbria — the highest point of the Pennines. It is England's only named wind. The Helm arrives with a distinctive formation: a bank of cloud, called the Helm, caps the summit like a helmet, and a parallel roll of cloud, called the Helm Bar, forms in the valley below. Between the two, the wind roars downslope with a violence that can knock people off their feet and strip tiles from roofs. It has been documented since at least the 17th century and remains incompletely understood.

A block of the earth's crust that remains elevated between two parallel faults while the blocks on either side drop downward to form grabens. The mountains of the Basin and Range province — long, narrow, north-south ranges separated by flat valleys — are horsts. The ranges did not rise; the basins fell. A horst is what's left standing when the ground on both sides gives way.

A steep, heavily crevassed section of a glacier where the ice flows over a cliff or sharp increase in gradient and fractures into a chaotic maze of seracs, crevasses, and unstable ice towers. An icefall is a waterfall made of ice, still moving but shattered by the terrain beneath it. The Khumbu Icefall on Everest is the most famous and most feared.

An isolated, steep-sided rock hill or mountain rising abruptly from a flat surrounding plain — literally an "island mountain." Inselbergs are residual landforms: the last resistant remnants of rock standing after everything around them has been eroded to flatness. Uluru (Ayers Rock) is the most famous. They are found in tropical, subtropical, and arid regions worldwide, and their steep flanks and summit isolation often support plant and animal communities found nowhere else in the surrounding landscape.

A snowpack condition in which the entire depth of snow is at the same temperature — 32°F / 0°C — meaning the whole pack is on the verge of melting. An isothermic snowpack is saturated, heavy, and structurally unstable. It is the condition that precedes wet avalanches and the final collapse of winter into spring.

 A sudden, catastrophic flood caused by the release of water from beneath or within a glacier — often triggered by volcanic activity beneath an ice cap, or by the failure of an ice dam holding back a glacial lake. Jökulhlaups can discharge millions of cubic feet of water per second, reshaping valleys in hours. Iceland, with its volcanoes under ice caps, is the type locality.

 A wind that flows downhill under the influence of gravity, formed when air in contact with a cold surface — a glacier, a snow-covered plateau, a mountain slope at night — becomes denser than the air around it and drains downslope. Katabatic winds range from gentle nocturnal breezes to the 200-mph piteraqs of Greenland.

The zone of stunted, wind-deformed trees at the upper limit of tree growth on a mountain — trees that survive the subalpine only by growing low, twisted, and flagged by the prevailing wind. A krummholz tree may be centuries old and only waist-high. The krummholz zone is the last stand of the forest — trees holding on at the edge of what is possible for a tree.

A fast-moving flow of volcanic debris and water — a slurry of mud, rock, ash, and meltwater that pours down the flanks of a volcano with the consistency of wet concrete and the speed of a river in flood. Lahars are triggered by eruptions melting glaciers and snow on a volcano's summit, by heavy rain mobilizing loose ash, or by the collapse of a crater lake. They follow river valleys, filling them wall to wall, and can travel 50 miles or more from the volcano. Lahars are among the deadliest volcanic hazards — more people have been killed by lahars than by lava flows.

A lens-shaped cloud formed by mountain waves — smooth, dome-like, stationary even in high wind. Forms on the lee side of summits as air rides a standing wave, cooling at the crest and condensing into cloud. Often mistaken for flying saucers. Formally: altocumulus lenticularis.

A compact, distinct section of a mountain range — a block of mountains that form a unified mass, often with a single identity. The Mont Blanc massif. The Denali massif. A massif is not a single peak but a cluster of peaks, ridges, and glaciers that read as one mountain body.

A flat-topped, steep-sided hill or mountain — wider than it is tall, its summit a remnant of a once-continuous layer of hard rock (often sandstone or basite lava) that has resisted the erosion consuming the softer material around it. Mesas are the desert's monuments, standing above the plains like tables set for no one. As erosion continues, a mesa narrows into a butte; a butte narrows into a pinnacle; and a pinnacle eventually falls.

An isolated hill or mountain that stands above a surrounding plain because it was composed of rock more resistant to erosion than the material that once surrounded it. A monadnock is what's left standing when everything around it has been worn away — the survivor in a landscape of attrition. An inselberg is the same concept in arid terrain; monadnock is the term used in temperate and humid regions.

 A ridge or mound of rock, gravel, and debris deposited by a glacier — the rubble it carried, pushed, and left behind. Terminal moraines mark the farthest advance of the ice. Lateral moraines line the valley walls. Medial moraines form where two glaciers merge, their lateral moraines combining into a dark stripe running down the center of the combined flow. Moraines are the glacier's autobiography, written in stone.

 A vertical shaft or tube in a glacier through which meltwater pours from the surface to the base. Moulins form when surface streams find a crevasse and begin to bore downward, the falling water enlarging the hole through thermal and mechanical erosion. The sound of water falling into a moulin is audible from a distance — a deep, roaring pour.

 The accumulation zone of a glacier where snowfall exceeds melt, and where firn is actively compacting into ice. Also used loosely as a synonym for firn itself.

 A rocky peak or ridge that protrudes through the surface of a glacier or ice sheet — an island of rock in a sea of ice. Nunataks are refugia: during glaciations, plants and animals survived on these ice-free summits while the world around them was buried. Some of the genetic diversity of modern alpine species can be traced to populations that held on, isolated, on nunataks.

A gently sloping, erosion-cut bedrock surface at the base of a mountain in an arid region, thinly veneered with sediment. Unlike a bajada (which is built up from deposited material), a pediment is carved down — the bedrock itself has been planed smooth by erosion. The distinction matters: a bajada is construction, a pediment is demolition. Both create the long, gradual slope between mountain and basin floor.

 Tall, thin blades of hardened snow or ice that form in clusters at high altitude, pointing toward the midday sun. They can range from a few centimeters to several meters tall and make travel across snowfields extremely difficult.

A pointed peak or sharp summit — a mountain with an unmistakable, aggressive profile. Used in the Southwest and Latin America for peaks that rise to a pronounced point. Picacho Peak in Arizona, visible for miles across the desert, is the type example.

The gently sloping region at the base of a mountain range — the transition between the steep mountains and the flat plain, built of sediment washed down from above. The Piedmont of the eastern United States, between the Appalachians and the Coastal Plain, is the type example: rolling hills on ancient, weathered rock, some of the oldest terrain on the continent.

 A katabatic wind that pours off the Greenland ice sheet and down the coastal mountains, reaching speeds of up to 200 miles per hour. One of the most powerful winds on Earth. It occurs when cold, dense air pooled on the ice cap spills over the edge and accelerates downslope.

A fast-moving, ground-hugging avalanche of superheated gas, volcanic ash, pumice, and rock fragments that races down the slopes of an erupting volcano at speeds up to 450 miles per hour and temperatures up to 1,300°F. A pyroclastic flow is unsurvivable. It incinerates and buries everything in its path. The destruction of Pompeii in 79 AD, of Saint-Pierre in 1902, and the devastation around Mount St. Helens in 1980 were all caused by pyroclastic flows.

The dry area on the leeward side of a mountain range, created when moist air is forced upward over the mountains, drops its moisture as precipitation on the windward side, and arrives on the other side warm, dry, and wrung out. The rain shadow is the mountain's gift to one side and its theft from the other. Eastern Oregon, Nevada, and the Owens Valley of California exist in the rain shadow of the Cascades and the Sierra Nevada.

 Avalanche.

A slope of small, loose, broken rock fragments accumulated at the base of a cliff or steep slope — finer than talus, typically ankle-deep, and miserable to ascend. Every step slides backward. Scree slopes are the debris fields of mountains slowly breaking apart.

 A tower or pinnacle of ice, formed where a glacier fractures into chaotic blocks as it flows over a steep drop — an icefall. Seracs are unstable, beautiful, and lethal. They can be the size of houses, standing at improbable angles, and they collapse without warning. Climbing through a serac field is a calculated gamble with time.

A stone-built shelter used during summer grazing months on the Hebridean or Highland moor. The journey to the shieling alone was a coming-of-age moment for a child. The paths to shielings were cairned onto the moor as guide-lines through the bog.

Terrain accessible from a ski resort's lifts or boundaries but outside the patrolled, controlled area. Neither fully backcountry nor resort skiing — a liminal zone where the infrastructure ends but the mountains continue.

 Fine snow or ice particles blown from a ridge or summit by the wind, streaming off the peaks like smoke. Also used for sea spray carried by gale-force winds.

A thin, breakable layer of refrozen snow formed when the sun melts the surface during the day and cold air freezes it at night. The crust may hold your weight for a step or two before giving way — a sustained betrayal.

Bowl-shaped depressions that form on a snow surface through uneven melting caused by solar radiation. The cups deepen as dirty or darker patches absorb more heat. A late-season snowfield covered in suncups looks like the surface of a golf ball.

A sharp, reversing turn in a trail or road ascending a steep slope, zigzagging back and forth to reduce the gradient. Switchbacks trade distance for steepness — you walk farther but climb more gently. They are the engineering solution to the problem of gravity on foot, and they shape how we experience mountains: slowly, in lateral traverses, with the view changing at every turn.

 A field of broken rock that has fallen from the cliff above and accumulated at its base. Larger than scree — individual rocks range from grapefruit-sized to refrigerator-sized. Crossing a talus field is an exercise in choosing which rocks to trust.

A small, deep mountain lake, especially one occupying the floor of a cirque or sitting in a glacially scoured basin above treeline. Clear, cold, and usually without a visible inlet or outlet. The kind of water that stops you in your tracks.

A level or nearly level surface cut into a slope, creating a step in the hillside. Terraces have been used for agriculture on every inhabited continent — from the rice terraces of Bali and the Philippines to the Inca andenes of Peru to the dry-farmed slopes of the Mediterranean. They turn gravity from an enemy into a tool, holding soil and water in place on ground that would otherwise shed both.

The elevation above which trees cannot grow — the boundary between forest and alpine tundra, drawn by cold, wind, desiccation, and the shortness of the growing season. Timberline is not a line but a zone: the forest thins, the trees shrink and twist into krummholz, and then, above a certain altitude, they stop. The line varies by latitude, aspect, and local conditions — roughly 11,500 feet in Colorado, 6,000 in the northern Cascades, at sea level in the Arctic.

 A cold, dry wind that blows from the north or northwest across southern France and into the western Mediterranean — similar to the mistral but originating over the Pyrenees or the Massif Central rather than the Alps. In Italian, tramontana means both the north wind and the North Star.

The seasonal movement of grazing animals — and the people who tend them — between lowland winter pastures and highland summer pastures. Not nomadism; transhumance is a fixed annual circuit between two known places, the rhythm of the year written into the movement of flocks.

A visible boundary on the wall of a glacier valley marking the maximum recent thickness of the ice — a horizontal line separating weathered rock above (which was exposed to the sky) from polished or unweathered rock below (which was covered by ice). The trimline is the glacier's high-water mark, etched into the valley wall. As glaciers thin and retreat, trimlines become increasingly visible — stark evidence of how much ice has been lost.

Newfoundland term for wind-dwarfed groves of spruce and fir, shoulder-height or lower, impossibly dense and tangled. Can grow for centuries without ever reaching above your chin. Related to krummholz and elfinwood, but nastier to walk through — a scrum of fairy-tale hags, all hunches and claws.

The slow, large-scale rising of a portion of the earth's crust — driven by tectonic compression, magma intrusion, or the removal of weight (such as the melting of an ice sheet). Uplift is the force that builds mountains, raises coastlines above the sea, and exposes marine fossils on mountaintops. It operates on timescales that make it invisible to any single human life, but its evidence is everywhere: tilted sedimentary layers, raised beaches, river terraces perched high above the current channel. The Himalayas are still rising. Scandinavia is still rebounding from the weight of ice that melted 10,000 years ago.

 A thin, transparent glaze of ice over rock. Extremely hazardous — crampons can't penetrate it and rock shoes can't grip it. The rock looks bare until you touch it and your hand slides.

A hard, dense layer of snow formed by sustained wind compaction. Smooth on the surface but brittle — it can fracture into slabs and slide. Windboard is one of the primary building blocks of slab avalanches.

 A warm, dry foehn wind that blows from the west across the Andes and down into western Argentina, mainly in winter. It arrives hot and desiccating, sometimes carrying dust, and can raise temperatures by 10°C in minutes.