An ice cave is any type of natural

cave Caves or caverns are natural voids under the Earth's Planetary surface, surface. Caves often form by the weathering of rock and often extend deep underground. Exogene caves are smaller openings that extend a relatively short distance undergrou ...

(most commonly

lava tubes A lava tube, more rarely called a pyroduct, is a 'roofed conduit through which molten lava travels away from its vent'. If lava in the tube drains out, it will leave an empty cave. Lava tubes are common in low-viscosity volcanic systems. La ...

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

caves) that contains significant amounts of perennial (year-round)

ice Ice is water that is frozen into a solid state, typically forming at or below temperatures of 0 ° C, 32 ° F, or 273.15 K. It occurs naturally on Earth, on other planets, in Oort cloud objects, and as interstellar ice. As a naturally oc ...

. At least a portion of the cave must have a temperature below 0 °C (32 °F) all year round, and

water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...

must have traveled into the cave’s cold zone.

Terminology

This type of cave was first formally described by Englishman Edwin Swift Balch in 1900, who suggested the French term ''glacieres'' should be used for them, even though the term ''ice cave'' was then, as now, commonly used to refer to caves simply containing year-round ice. Among speleologists, ''ice cave'' is the proper English term. A cavity formed ''within'' ice (as in a glacier) is properly called a

glacier cave A glacier cave is a cave formed within the ice of a glacier. Glacier caves are often called ice caves, but the latter term is properly used to describe bedrock caves that contain year-round ice. Overview Glacier caves form in the bottom edge ...

Types

Ice caves occur as static ice caves, such as Peña Castil Ice Cave, and dynamic or cyclical ice caves, such as Eisriesenwelt.

Temperature mechanisms

In most of the world,

bedrock In geology, bedrock is solid rock that lies under loose material ( regolith) within the crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface material. An exposed portion of bed ...

caves are thermally insulated from the surface and so commonly assume a near-constant temperature approximating the annual average temperature at the surface. In some cold environments, such as that surrounding

Mount Erebus Mount Erebus () is the southernmost active volcano on Earth, located on Ross Island in the Ross Dependency in Antarctica. With a summit elevation of , it is the second most prominent mountain in Antarctica (after Mount Vinson) and the second ...

, average surface (and thus cave) temperatures are below freezing, and with surface water available in summer, ice caves are possible and are sometimes overlain by

fumarolic ice tower A fumarolic ice tower is a tower of ice produced by fumaroles of volcanic activity in an environment whose ambient temperature is below the freezing point of water. They are often underlain by large ice caves. Mount Erebus Mount Erebus ( ...

s. However, many ice caves exist in

temperate In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ran ...

climates, due to mechanisms that result in cave temperatures being ''colder'' than average surface temperatures where they formed. ''Cold traps'': Certain cave configurations allow seasonal

convection Convection is single or Multiphase flow, multiphase fluid flow that occurs Spontaneous process, spontaneously through the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoy ...

to import cold

air An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosph ...

from the surface in winter, but not warm air in summer. A typical example is an underground chamber located below a single entrance. In winter, cold

dense Density (volumetric mass density or specific mass) is the ratio of a substance's mass to its volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' (or ''d'') can also be use ...

air settles into the cave, displacing any warmer air which rises and exits the cave. In summer, the cold cave air remains in place as the relatively warm surface air is lighter and cannot enter. The cave will only exchange air when the surface air is cooler than the cave air. Some cold traps may ensnare surface

snow Snow consists of individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water througho ...

and shade it from the summer

sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

’s rays, which may further contribute to the colder cave temperature. ''Permafrost'': Even temperate environments can include pockets of bedrock that are below freezing year round, a condition called

permafrost Permafrost () is soil or underwater sediment which continuously remains below for two years or more; the oldest permafrost has been continuously frozen for around 700,000 years. Whilst the shallowest permafrost has a vertical extent of below ...

. For example, winter wind and an absence of snow cover may allow freezing deep enough to be protected from summer thaw, particularly in light-colored

rock Rock most often refers to: * Rock (geology), a naturally occurring solid aggregate of minerals or mineraloids * Rock music, a genre of popular music Rock or Rocks may also refer to: Places United Kingdom * Rock, Caerphilly, a location in Wale ...

that does not readily absorb heat. Although the portion of a cave within this permafrost zone will be below freezing, permafrost generally does not allow water

percolation In physics, chemistry, and materials science, percolation () refers to the movement and filtration, filtering of fluids through porous materials. It is described by Darcy's law. Broader applications have since been developed that cover connecti ...

, so ice formations are often limited to

crystals A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macrosc ...

from

vapor In physics, a vapor (American English) or vapour (Commonwealth English; American and British English spelling differences#-our, -or, see spelling differences) is a substance in the gas phase at a temperature lower than its critical temperature,R ...

, and deeper cave passages may be arid and completely ice-free. Ice caves in permafrost need not be cold-traps (although some are), provided they do not draught significantly in summer. ''Evaporative cooling'': In winter, dry surface air entering a moisture-saturated cave may have an additional cooling effect due to the

latent heat Latent heat (also known as latent energy or heat of transformation) is energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process—usually a first-order phase transition, like melting or condensation. ...

evaporation Evaporation is a type of vaporization that occurs on the Interface (chemistry), surface of a liquid as it changes into the gas phase. A high concentration of the evaporating substance in the surrounding gas significantly slows down evapora ...

. This may create a zone within the cave that is cooler than the rest of the cave. Because many caves have seasonally-reversing draughts, the corresponding warming of the cave through

condensation Condensation is the change of the state of matter from the gas phase into the liquid phase, and is the reverse of vaporization. The word most often refers to the water cycle. It can also be defined as the change in the state of water vapor ...

in summer may occur at a different location within the cave, but in any event a moisture-saturated cave environment is likely to experience much more

evaporative cooling An evaporative cooler (also known as evaporative air conditioner, swamp cooler, swamp box, desert cooler and wet air cooler) is a device that cools air through the evaporation of water. Evaporative cooling differs from other air conditioning sy ...

than condensative warming.

Types of ice

Different freezing mechanisms result in visually and structurally distinct types of perennial cave ice. ''Ponded water'': Surface water that collects and ponds in a cave before freezing will form a clear ice mass, and can be tens of metres thick and of great age. Large ice masses are

plastic Plastics are a wide range of synthetic polymers, synthetic or Semisynthesis, semisynthetic materials composed primarily of Polymer, polymers. Their defining characteristic, Plasticity (physics), plasticity, allows them to be Injection moulding ...

and can slowly flow in response to gravity or pressure from further accumulations. Sculpting from air flow and sublimation may reveal ancient accumulation bands within the ice. ''Accumulated snow'': Compressed under the weight of ongoing accumulations, snow sliding or falling into a cave entrance may eventually form ice that is coarsely crystalline, akin to

glacier A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

ice. True underground glaciers are rare. ''Ice formations'': Water that freezes before ponding may form

icicle An icicle is a spike of ice formed when water falling from an object freezes. Formation and dynamics Icicles can form during bright, sunny, but subfreezing weather, when ice or snow melted by sunlight or some other heat source (such as a poor ...

s, ice-

stalagmite A stalagmite (, ; ; ) is a type of rock formation that rises from the floor of a cave due to the accumulation of material deposited on the floor from ceiling drippings. Stalagmites are typically composed of calcium carbonate, but may consist ...

s, ice columns or frozen

waterfall A waterfall is any point in a river or stream where water flows over a vertical drop or a series of steep drops. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf. Waterfalls can be formed in seve ...

s. ''Airborne moisture (water vapor)'': Freezing vapor can form

frost Frost is a thin layer of ice on a solid surface, which forms from water vapor that deposits onto a freezing surface. Frost forms when the air contains more water vapor than it can normally hold at a specific temperature. The process is simila ...

crystals, frost feathers and two-dimensional ice plates on the cave walls and ceiling. '' Needle ice'': Infiltrating water that freezes within the bedrock can sometimes be forced into the cave passage. ''Intrusions'': The weight of a surface glacier perched atop a cave entrance can force glacial ice a short distance into the cave. The only known examples of this phenomenon are the several 'ice plugs' at the back of Castleguard Cave in

Alberta Alberta is a Provinces and territories of Canada, province in Canada. It is a part of Western Canada and is one of the three Canadian Prairies, prairie provinces. Alberta is bordered by British Columbia to its west, Saskatchewan to its east, t ...

Examples

* Bandera Volcano Ice Cave (New Mexico, United States) * Bixby State Preserve (Iowa, United States) * Booming Ice Chasm (Alberta, Canada) * Bortig Pit Cave (Apuseni Mountains, Romania) * Canyon Creek Ice Cave (Alberta, Canada) * Castleguard Cave (Alberta, Canada) * Coudersport Ice Mine (Pennsylvania, United States) * Decorah Ice Cave State Preserve (Iowa, United States) * Demänovská Ice Cave (Slovakia) * Dobšiná Ice Cave (Slovakia) UNESCO World Heritage site (2000) * Eisriesenwelt (Werfen, Austria) * Grotta del Gelo (Sicily, Italy) * Grotte Casteret (Aragon, Spanish Pyrenees) * Ice Mountain (West Virginia, United States) * Kungur Ice Cave (Perm Krai, Russia) * Merrill Cave (

Lava Beds National Monument Lava Beds National Monument is located in northeastern California, in Siskiyou County, California, Siskiyou and Modoc County, California, Modoc counties. The monument lies on the northeastern flank of Medicine Lake Volcano, which is the largest ...

, California) * Narusawa Ice Cave, (Mount Fuji, Japan) * Niter Ice Cave (Idaho, United States) * Sam's Point Preserve (New York, United States) * Scărișoara Cave (Romania)Scarisoara Ice Cave – the biggest underground glacier in Romania
Travel Guide Romania website, December 24, 2014, retrieved 17 January 2016. * Schellenberg Ice Cave (Bavaria, Germany) *

Shawangunk Ridge The Shawangunk Ridge , also known as the Shawangunk Mountains or The Gunks, is a ridge of bedrock in Ulster County, Sullivan County and Orange County in the state of New York, extending from the northernmost point of the border with New Jers ...

(New York, United States) * Víðgelmir (West Iceland)

References

External links

goodearthgraphics.com
Video of an ice cave in the Big Snowy Mountains of Montana
YouTube video *Rod Benso

For Montana website, selfpublished, 2009, retrieved 17 January 2016.

Eisriesenwelt Austria, undated. retrieved 17 January 2016
Durmitor Ice Cave

Speleoglacio Ice Cave Research Group
University of Milano, Italy *Marco Pleban
GROTTE DI GHIACCIO
Marco Plebani website, June 2009, 3pp (in Italian), retrieved 17 January 2016. {{Authority control Water ice