ABSTRACT
Cooling by Unidirectional Ventilation During the winter, multi-entrance caves promote gravity drainage of dense outside air into the cave, which can cool the rock to below 0°C. In the summer, air within the cave, being cooler than outside, drains to lower entrances drawing in warmer air from outside. For ice to form in these circumstances, mean annual temperatures need to be below 0°C and while this condition is met in some regions, such as in mountainous western North America, it is likely that cave trap conditions with perennial ice are also required. Silvestru (1999) argues that no temperate ice caves are known in which perennial ice is sustained by this mechanism.
