Le ander da La Crusc
The Snow Cave at Sas dla Crusc/Santa Croce
The Snow Cave at Sas dla Crusc - le ander da La Crusc in Ladin language - is a natural cave which is formed by the snowmelt in the spring months and sometimes remains intact until the following winter. However, if only small amounts of snow fall in the winter, the cave will not form.
During particularly cold and snowy winters, accumulations of snow remain in shaded areas and compact into large ice masses. Accumulations of scree and mud insulate the surface.
The melt water flows down the mountain and underneath the ice masses and even though the temperature of the water is only just above freezing point, as it runs though, it carves out a small cave underneath the layers of ice.
The cave continues to grow in size in the summer: the narrow hollow carved out by the stream is filled with cold air which is denser and therefore heavier than the summer air outside. This in turn sets off an inverted chimney effect: the heavy cold air sinks down to the bottom of the cave, giving rise to a strong draught from the top to the bottom of the snow cave. Warm summer air is now drawn into the cave from the upper openings, causing the cave to melt from within.
In the meantime, the warm is cooled by the ice and thus flows out through the lower opening as heavy air. This effect can continue for months, melting an ever larger cavity in the ice.