An ice volcano is a conical mound of ice formed over a terrestrial

lake A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from ...

via the eruption of

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 ...

and slush through an

ice shelf An ice shelf is a large platform of glacial ice floating on the ocean, fed by one or multiple tributary glaciers. Ice shelves form along coastlines where the ice thickness is insufficient to displace the more dense surrounding ocean water. T ...

. The process is wave-driven, with wind providing the energy for the waves to cut through the ice and create formations that loosely mimic the shape and activity of

volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...

es. After being ejected into the atmosphere, the liquid water and slush freeze and fall back to the surface, growing the formation.

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 ...

may also be erupted. The phenomenon is most often observed along the southern coast of

Lake Erie Lake Erie ( ) is the fourth-largest lake by surface area of the five Great Lakes in North America and the eleventh-largest globally. It is the southernmost, shallowest, and smallest by volume of the Great Lakes and also has the shortest avera ...

and

Lake Ontario Lake Ontario is one of the five Great Lakes of North America. It is bounded on the north, west, and southwest by the Canadian province of Ontario, and on the south and east by the U.S. state of New York (state), New York. The Canada–United Sta ...

, when the temperature is below freezing and the wind blows onshore with a velocity of at least . They are known to reduce

coastal erosion Coastal erosion is the loss or displacement of land, or the long-term removal of sediment and rocks along the coastline due to the action of Wind wave, waves, Ocean current, currents, tides, wind-driven water, waterborne ice, or other impacts ...

there. The formations are temporary: they are frequently destroyed by storms and warm weather, and once the lake wholly freezes over, eruptions are no longer possible. There is no consensus name for this phenomenon. Due to its visual similarity to volcanism and particularly

cryovolcanism A cryovolcano (sometimes informally referred to as an ice volcano) is a type of volcano that erupts gases and volatile material such as liquid water, ammonia, and hydrocarbons. The erupted material is collectively referred to as ''cryolava''; ...

, the term "ice volcano" is frequently used, but it remains controversial. Unlike

geysers A geyser (, ) is a spring with an intermittent water discharge ejected turbulently and accompanied by steam. The formation of geysers is fairly rare and is caused by particular hydrogeological conditions that exist only in a few places on Ea ...

and related structures, ice volcanoes are not

hydrothermal Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...

. The uplifts may attract a number of visitors, but they are dangerous, and experts warn that people may fall through the ice or slip into the cold lake. Ice volcanoes are used by snowy owls as hunting platforms to search for

waterfowl Anseriformes is an order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae (three species of screamers), Anseranatidae (the magpie goose), and Anatidae, the largest family, which i ...

Formation

These features are distinct from pressure ridges, which are uplifts formed by the compression of ice against a shoreline or another floe. Instead, ice volcanoes are created by waves colliding with irregularities at the edge of an ice sheet. The abnormalities concentrate the wave energy in a small area, where the ice is eroded to form a V-shaped channel. Spray, ice, and slush splashing out of the feature create a volcanic cone at the channel's shoreward end. This process takes only a few hours. The lakeward end of the channel may then be sealed by ice, but the volcano may continue to erupt. A wave

amplitude The amplitude of a periodic variable is a measure of its change in a single period (such as time or spatial period). The amplitude of a non-periodic signal is its magnitude compared with a reference value. There are various definitions of am ...

of at least is needed to induce eruptions, so ice volcanoes are rarely active without storm-force winds. Formation near land is suppressed by

reef A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic component, abiotic (non-living) processes such as deposition (geol ...

s and

shoals In oceanography, geomorphology, and geoscience, a shoal is a natural submerged ridge, bank, or bar that consists of, or is covered by, sand or other unconsolidated material, and rises from the bed of a body of water close to the surface or ...

, which absorb the wave energy needed for the phenomenon. Nonetheless, they may produce larger cones further out at sea, where the greater depth makes this possible. Formation is more thoroughly suppressed by powerful storms, which erode the ice too fast for mound creation. One type of ice volcano, known as a "cold spot", does not require waves to break against the edge of an ice shelf. Instead, water and slush erupt through a region of weak ice near the coast and form a mound. This is analogous to a geological hotspot.

Appearance and eruptions

Landfast ice is required, so the volcanoes normally form near land. They are found in successive rows, and within one row, the features usually have equal height and spacing. However, when comparing two rows, the height and spacing may be drastically different. Ice volcanoes range in height from less than one meter to ten meters, with the largest ones located far from the shore. Eruptions over ten meters high have been observed, but it is believed that the height of the eruptions are proportional to the size of the mounds. A single eruption may increase the height of the volcano by several centimeters. When an eruption occurs above , however, the water erodes the uplift instead of expanding it. Spacing is determined by the amplitude and direction of the waves. In general, the appearance and number of ice volcanoes change considerably between winters. Different types of ice volcanoes have been compared to

shield volcano A shield volcano is a type of volcano named for its low profile, resembling a shield lying on the ground. It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more viscous lava ...

es and

stratovolcano A stratovolcano, also known as a composite volcano, is a typically conical volcano built up by many alternating layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with ...

es. They are noted for their symmetry. Cold spot volcanoes are particularly symmetrical, but their eruption has not been observed.

Formation

Appearance and eruptions

References

Further reading