Ice caves adjacent to Lower Erebus Hut, formed by areas of volcanically warmed ground that melt cavities beneath the snow cover. The atmosphere inside the caves is 0°C and 100% humidity, which results in large ice crystals growing from the vapor. Dripping water forms ice stalagmites, stalactites, curtains, and other features more commonly associated with limestone caves. Steam rising from cave entrances freezes where it meets the -30°C outside air forming ice chimneys up to 20M high. Inside the caves, glassy surfaces of lava flows are preserved in contrast to those outside the caves which are subjected to acidic volcanic gasses and mechanical erosion from blowing snow. The delicate, wiggling ice form seen here was called "Angel's pubes" (or pubic hairs) by Dr. Bill McIntosh, who is visible in the background.