In extensively glaciarized permafrost areas such as Northern Victoria Land, rock glaciers are quite common and are considered postglacial cryotic landforms. This paper reveals that two rock glaciers in Northern Victoria Land (at Adélie Cove and Strandline) that are located close to the Italian Antarctic Station (Mario Zucchelli Station) should have the same origin, although they were previously mapped as Holocene periglacial landforms and subsequently considered ice‐cored and ice‐cemented rock glaciers, respectively. In fact, by integrating different geophysical investigations and borehole stratigraphy, we show that both landforms have similar internal structures and cores of buried glacier ice. Therefore, this kind of rock glacier is possibly related to the long‐term creep of buried ice rather than to permafrost creep alone. This interpretation can be extended to the larger part of the features mapped as rock glaciers in Antarctica. In addition, a high‐reflective horizon sub‐parallel to the topographic surface was detected in Ground Probing Radar (GPR) data over a large part of the study area. Combining all the available information, we conclude that it cannot be straightforwardly interpreted as the base of the active layer but rather represents the top of a cryo‐lithological unit characterized by ice lenses within sediments that could be interpreted as the transition zone between the active layer and the long‐term permafrost table. More generally, knowledge of the subsurface ice content and, in particular, the occurrence of massive ice and its depth is crucial to make realistic and affordable forecasts regarding thermokarst development and related feedbacks involving GHG emissions, especially in the case of cryosoils rich in carbon content. Copyright © 2017 John Wiley & Sons, Ltd.

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Thermokarst depressions are widespread phenomena due to permafrost degradation in the Arctic, whereas only few are known from mountain permafrost of the mid-latitudes. In the Italian Central Alps, close to the Stelvio Pass (2,763 m above sea level), a ski run was built in 1987. Since 1981, statistically significant air warming has been recorded, especially during summer (+0.65 C per decade). Permafrost temperature recorded at the nearby Share Stelvio Borehole between 1990 and 2011 exhibited a rapid increase (> 0.8 C per decade) and an active-layer thickening (7 cm/year).Between the years 1999 and 2003, some thermokarst depressions started to develop, initially in the lower part of the ski run and then extending to higher elevations. The depressions increased in number, size, and depth with time. Since ski-run construction, the area remained free of vegetation until early 2000, when vegetation colonization started, showing a coupling with the onset of thermokarst development and summer warming. Vegetation changes accelerated with the ingress of pioneer and early-successional as well as of late-successional species. Moreover, the ingress of shrub species (Salix spp.) typical of lower elevation belts (subalpine and even montane) was dated to 2004. All the observed features show a rapid and coupled response of the abiotic and biotic components of this ecosystem to climate warming.Our data also confirm the similarity of the observed responses and dynamics of the alpine tundra with the Arctic tundra with regard to both permafrost and vegetation.

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