The identification of hazardous slopes with degrading permafrost is a key task in the mountain periglacial environment. If rockslides have previously been preconditioned by rock wall permafrost, similar events may be triggered from present unstable rock walls. An inventory of rockslides and rock avalanches in the austral part of the Santa Cruz river basin (31 degrees 40 '-31 degrees 50 ' S, 70 degrees 30 '-70 degrees 10'W), San Juan, Argentina, was made. The study area comprises a surface of approximately 432 km(2) (50% above 3,500 m asl); 15 rockslides, 12 complex rockslides evolving to rock avalanches and 19 rock avalanches were identified. The deposits were analyzed with remote sensory imagery and during fieldwork in order to study processes under permafrost degradation caused by global warming. Rock sampling procedures and laboratory rock-resistivity testing were also carried out. We characterized the detachment scars and deposits for two rockslides. Two different mechanisms were identified. In one rockslide, shallow active layer detachment was favored by shear-displacement along pre-existing joints, as a result of short-term periods of climate warming. In the other, long-term permafrost degradation favored a deeper failure process. The studied landslide processes could not be explained by permafrost degradation alone. Faults, the geometric arrangement of their structural elements and seismic activity may contribute to trigger these phenomena. It is expected that the magnitude and frequency of rockslide hazards will increase during the 21st century.

In the global warming trend, the permafrost area is decreasing. And the change of temperature seriously affects the safety and stability on Open-pit slope under the alternation of freezing and thawing. Based on FLAC(3D), the simplified algorithm of THM coupling with phase change is developed and upgraded again. The change law of failure area in one time freezing and thawing and various stability influence factors of the permafrost slope were discussed by yielding approach index. The results show that the frozen slope is local failure, from April to July is danger every year, and that the freezing temperature increment and the height of slope are still the main influence factors and that the water content, the times of freeze-thaw cycles and the temperature increment of surrounding boundary are severely affect the stability of the slope. And the research can be a significance reference for further understanding the slope stability under freeze-thaw cycles.

Numerous rock fall events in the European Alps suggest an increasing occurrence of mass movements due to rising temperatures. In recent years particularly during extensive hot periods large numbers of rock fall events have been reported (e.g. hot summers of 2003, 2005 and 2012). Governed by climate change two major changes can be observed at the summit region of the Kitzsteinhorn, Austria: Intensive glacier retreat and changes of permafrost conditions. The combination of these two major changes leads to an increasing exposure of potentially hazardous areas and higher risks for man and infrastructure. Close to the summit, infrastructure was built in the 1960s, including a cable car station at 3029 m on a north exposed rock face w under permafrost conditions. Due to the decreasing surface area of the glacier and the deepening of the annual active layer, meter thick slabs of the slope became unstable and started sliding down slope parallel to bedding planes. In order to avoid a continuous and deep-reaching destabilization of the entire slope, an intensive rehabilitation program has been established. This program consists of short-, mid- and long-term measures with technical installations (drainage, rock support, etc.) and an intensive monitoring program (including laser scanning, continuous geophysical, geotechnical and temperature monitoring).

We present a review of the changing state of European permafrost within a spatial zone that includes the continuous high latitude arctic permafrost of Svalbard and the discontinuous high altitude mountain permafrost of Iceland, Fennoscandia and the Alps. The paper focuses on methodological developments and data collection over the last decade or so, including research associated with the continent-scale network of instrumented permafrost boreholes established between 1998 and 2001 under the European Union PACE project. Data indicate recent warming trends, with greatest warming at higher latitudes. Equally important are the impacts of shorter-term extreme climatic events, most immediately reflected in changes in active layer thickness. A large number of complex variables, including altitude, topography, insolation and snow distribution, determine permafrost temperatures. The development of regionally calibrated empirical-statistical models, and physically based process-oriented models, is described, and it is shown that, though more complex and data dependent, process-oriented approaches are better suited to estimating transient effects of climate change in complex mountain topography. Mapping and characterisation of permafrost depth and distribution requires integrated multiple geophysical approaches and recent advances are discussed. We report on recent research into ground ice formation, including ice segregation within bedrock and vein ice formation within ice wedge systems. The potential impacts of climate change on rock weathering, permafrost creep, landslides. rock falls, debris flows and slow mass movements are also discussed. Recent engineering responses to the potentially damaging effects of climate warming are outlined, and risk assessment strategies to minimise geological hazards are described. We conclude that forecasting changes in hazard occurrence, magnitude and frequency is likely to depend on process-based modelling, demanding improved understanding of geomorphological process-response systems and their impacts on human activity. (C) 2008 Published by Elsevier B.V.

We modeled the sensitivity of six ice-cemented slope deposits from the western McMurdo Dry Valleys, Antarctica to failure by shallow, thaw-induced planar sliding. The deposits examined have purportedly remained physically stable, without morphologic evidence for downslope movement, for millions of years. Could they fail in the near future from greenhouse-induced warming? To address this question, we first prescribed various increases in mean summertime soil surface temperature (MSSST) and modeled numerically the resultant changes in soil thaw depths using a one-dimensional heat diffusion equation (including the effects of latent heat of fusion). Second, we calculated the minimum thaw depths required to facilitate failure by shallow planar sliding for each deposit, for all numerical simulations, we maintained present soil-moisture conditions and used a Mohr-Coulomb-based equation of safety factor. Third, we calculated the rate of subsurface meltwater flow assuming Darcy's Law. Our results show that although most deposits contain sufficient subsurface ice to induce sliding upon thawing, lateral rates of water flow of as much as similar to 40 m/day for some colluvial deposits prohibit the build-up of requisite pore pressures for failure. On the other hand, silty deposits, that contain gravimetric water >= 15%, occur on slopes > 20 degrees, and possess low hydraulic conductivities (similar to 30-60 cm/day), common in the Dry Valleys region, could fail if MSSST, and by inference mean summertime atmospheric temperatures, increase by 4 to 9 degrees C. This temperature increase is similar to that predicted to occur from greenhouse-induced wart-ning in Antarctica over the next century. (c) 2007 Elsevier B.V. All rights reserved.