A fascinating feature of mountain permafrost is the phenomenon of so-called “rock glaciers”. These ice-debris landforms, often characterized by a striking “porridge-like” or “lava stream-like” appearance are created by the slow, viscous creep of ice-rich permafrost.

Core drillings and geophysical soundings have shown that the ice content of such creeping permafrost commonly exceeds the volume of rock particles by about a factor of two. This condition known as “ice supersaturation”, “excess ice” or “ice with rock inclusions” enables sustained long-term creep deformation. Modern techniques such as exposure dating of surface blocks demonstrate that many active rock glaciers have been moving continuously for thousands of years since the end of the last Ice Age.

Global warming is causing permafrost temperatures to increase. As a result, the creeping mixtures of rock and ice become warmer and more easily deformable. In marked contrast to glaciers, which are generally retreating, many rock glaciers have recently tended to accelerate their movement and have continued advancing. Information on their distribution and evolution is systematically collected as part of global permafrost and climate monitoring.