Ice can take on a variety of forms in caves similar to the most common of depostional formations, such as stalactites, stalagmites, flowstone, and curtains. These typically form from water flowing or dripping into the cave, and crystal faces aren't evident. More unusual forms such as harilike strands and hexagonal crystals may occur when ice freezes from water vapor.

In almost any cave in areas that reach below freezing temperatures in winter, ice formations may be seen in entrance zones regardless of the ambient temperature further in the cave. Lava tubes often act as cold air traps, with cold winter air sinking and allowing ice formations to form that may persist well after surface temperatures have risen in the spring. As warmer air wafts through the cave, it may melt the ice into bizarre rounded shapes with bulbous tops known as schmos.

The most spectacular ice formations are those in alpine caves where the cave's ambient temperature stays at or below the freezing point year-round. One of the best known of these is the touristic Eisriesenwelt Cave in Austria. In the USA, few of these are known but perhaps the best-known is the undeveloped Fossil Mountain Ice Cave of Wyoming.

The terminology for caves with perennial ice has been a bit confused. They have long been called sinply "ice caves" in English. Englishman Edwin Swift Bach suggested that these caves be named by their French name, Glacieres, in his seminal 1900 work Glacieres and Freezing Caverns. But even Edwin acknowledged that people were unlikely to adopt the French term, and "ice cave" continues to be the most popular term used for these caves by both the public and most geologists. Caves actually formed IN ice are commonly called Glacier Caves by glaciologists.



Broomstick ice stals in a lava tube

Massive ice deposits in a lava tube


Permanent ice can take on a blue-green cast.

Deflected ice stalactites and stalagmites in a lava tube


Where water flows along freezing ceilings, ice draperies can form.


Hexagonal ice crystals on the ceiling in a limestone cave. These form from water vapor.

 
Ice columns melted by warmer air currents Large ice formations and sheet ice on the floor of a lava tube Unusual ice needles probably formed from water vapor Schmos, ice stalagmites sculpted by air currents

More ice images: select for a larger image.

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The Virtual Cave

Created: December 14, 2006
Updated: Feb. 26, 2013
Author: Dave Bunnell