Mysterious "frost mounds" dotted across Siberia sometimes burst to form giant craters — and now, scientists have taken a step closer to discovering what makes these strange humps pop.
Frost mounds are areas of the permafrost that bulge as fluids accumulate beneath the surface. According to ongoing research at the Siberian Branch of the Russian Academy of Sciences (SBRAS), two distinct "systems" can lead to this bulging: open and closed. In an open system, water and gas pooling beneath the permafrost move around and leak to the surface through cracks. But in a closed system, water and gas are trapped in a pocket that inflates, putting increasing pressure on the permafrost.
