Formation of the cave
The Eisriesenwelt is a cave labyrinth with a total length of more than 40 kilometers. It was created over a very long time period. The first cracks and fissures in the limestone caves began to form during tectonic elevations about 100 million years ago. Chemical dissolution processes and water erosion across the millennia caused the subterranean cracks to increase, leading to the development of immense hollow spaces.
Alpine caves are in a development process even today, even if many cave systems - including large sections of the Eisriesenwelt - are no longer changing significantly due to dehydration.
Ice inside the cave
Cave ice can be formed by a variety of processes. The Eisriesenwelt is a dynamic ice cave. This means that the cave galleries and fissures form a link from lower entrances to higher openings, which – like a chimney - allow the passage of air.
Depending on the outside climate, the temperature inside the mountain is either cooler or warmer, causing an air draft from top to bottom or vice versa due to the specific weight differences of the air. In the winter, when the air inside the mountain is warmer than outside, cold air enters into the passages and cools the lower part of the cave to below zero degrees.
This means that the melting water entering the rock fissures in the spring and dripping into the cooler areas of the cave will freeze, forming the spectacular ice sculptures in the interior of the mountain.
More detailed information on this topic is available in the printable PDF