Ice cave

Some cold traps may ensnare surface snow and shade it from the summer sun’s rays, which may further contribute to the colder cave temperature.

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 that does not readily absorb heat.

Ice caves in permafrost need not be cold-traps (although some are), provided they do not draught significantly in summer.

Different freezing mechanisms result in visually and structurally distinct types of perennial cave ice.

Large ice masses are plastic and can slowly flow in response to gravity or pressure from further accumulations.

Needle ice: Infiltrating water that freezes within the bedrock can sometimes be forced into the cave passage.