Grotta del Gelo ("Cave of Frost") is a volcanic cave of

Mount Etna Mount Etna, or simply Etna ( it, Etna or ; scn, Muncibbeḍḍu or ; la, Aetna; grc, Αἴτνα and ), is an active stratovolcano on the east coast of Sicily, Italy, in the Metropolitan City of Catania, between the cities of Messina ...

which is known for the presence of a large amount of ice. The cave formed in 1614-1624 during a large eruption of the volcano, inside one of the lava flows produced during that eruption. Within the two subsequent decades, ice grew and accumulated in the cave. Today it is a tourist destination.

Geography and geomorphology

Grotta del Gelo lies at - elevation on Etna's northern/northwestern flank, in the municipality of

Randazzo Basilica of Santa Maria Assunta. Randazzo ( scn, Rannazzu) is a town and '' comune'' in the Metropolitan City of Catania, Sicily, southern Italy. It is situated at the northern foot of Mount Etna, c. northwest of Catania. It is the nearest ...

and within the Etna National Park. The cave can be reached by foot from Piano Provenzana. Other caves in the area are the , and , the first two of which formed during the same eruption as the Grotta del Gelo. There are also two

volcanic cone Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and ...

s, Monte Nero and Monte Pizzillo, and the vents of the 1923 and 1947 eruptions in the area. The first record of the cave is found in Sartorius von Walterhausen's 1880 work, as "Bocche del Gelo".

Cave

This long and about wide

lava tube A lava tube, or pyroduct, is a natural conduit formed by flowing lava from a volcanic vent that moves beneath the hardened surface of a lava flow. If lava in the tube empties, it will leave a cave. Formation A lava tube is a type of lava ...

can be accessed through a wide entrance at the upper end of the tube. The cave formed during the 1614-1624 eruption of Etna, which formed the "lava dei Dammusi"

lava flow Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ...

s on Etna's western flank. Part of this lava flow system is the "Sciara del Follone" that contains the cave. This long-lasting eruption emplaced about of lava on a surface of about . The surface of the lava flows, exposed to the air, cooled and solidified to form a crust on the remaining flow. These crusts were left behind when the still-flowing lava in the cavities drained, leaving cavities of various shapes and sizes. Due to the great thickness of the lava flow – on average – it probably took at least a decade for it to cool sufficiently for ice to form within.

Ice

The cave contains about or of ice, which stacks on the cave floor and the walls. The ice is decorated with

stalagmite A stalagmite (, ; from the Greek , from , "dropping, trickling") 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 typicall ...

stalactite A stalactite (, ; from the Greek 'stalaktos' ('dripping') via ''stalassein'' ('to drip') is a mineral formation that hangs from the ceiling of caves, hot springs, or man-made structures such as bridges and mines. Any material that is soluble ...

s and ice columns. It fills the deeper parts of the cave. This body of ice has been called a

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

. Grotta del Gelo is not the only cave containing ice on Mount Etna; the ("Abyss of Ice") which formed in 1947 also contains ice deposits but is not accessible. Ice also forms in the Grotta del Lago lava cave above Grotta del Gelo, but it thaws during summer and is thus not perennial.

Ice changes

The ice within the cave began to form during the Maunder Minimum, within two decades from the formation of the cave – probably during the second half of the 17th century. The ice mass in the cave increased until the 1980s and then declined due to the combined effect of

climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...

and an eruption in 1981 which occurred close to the cave and changed its temperature regime. The shape of the ice body has also changed over time; at some time after the 1990s a gallery formed in the ice, which then disappeared again. A phase of increased ice volume during and after 2014 has been linked to heavy

snowfall Snow comprises 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 throughout ...

Use and scientific research

The cave was used as a source of water by

farmer A farmer is a person engaged in agriculture, raising living organisms for food or raw materials. The term usually applies to people who do some combination of raising field crops, orchards, vineyards, poultry, or other livestock. A farmer m ...

s, who brought their animals there. Despite being locally known for centuries, it does not appear to have been documented systematically until the late 20th century. The first known written reference was to the ''Bocche de Gelo'' ("Mouth of Frost") in 1880. Beginning in the 1970s the cave became a

tourist Tourism is travel for pleasure or business; also the theory and practice of touring, the business of attracting, accommodating, and entertaining tourists, and the business of operating tours. The World Tourism Organization defines tourism ...

attraction for hikers, which led to increasing scientific interest and investigations from the 1980s onwards. Its interior was monitored and investigated from 1997 to 2000, and in 2013 a new and improved sensor network was installed by researchers to track the cave's atmospheric humidity and temperature. It is probably the best known cave at Etna and of great volcano- speleological importance. Legends talk of the existence of a

treasure Treasure (from la, thesaurus from Greek language ''thēsauros'', "treasure store") is a concentration of wealth — often originating from ancient history — that is considered lost and/or forgotten until rediscovered. Some jurisdictions le ...

at Grotta del Gelo; such legends are common for the volcanic caves at Etna.

References

Sources

* * * Caves of Italy Glaciers of Italy Ice caves Lava tubes {{DEFAULTSORT:Grotta del Gelo