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Kellerer-Pirklbauer, A., Slupetzky, H. and Avian, M., 2012. Ice-avalanche impact landforms: the event in 2003 at the glacier Nördliches Bockkarkees, Hohe Tauern Range, Austria. Geografiska Annaler: Series A, Physical Geography, 94, 97-115. doi:10.1111/j.1468-0459.2011.00446.x ABSTRACT The hanging glacier Nördliches Bockkarkees (47° 07′ 21″ N; 12° 44′ 00″ E) represents the only Austrian glacier that formed large and hazardous ice avalanches over the last decades. Only one major ice avalanche was released between August 1993 and July 2011 underlying the rareness of such large ice avalanches in the Austrian Alps. The ice avalanche happened on 26 June 2003 and was very unusual for two reasons: First, the ice avalanche occurred suddenly without major signs of glacier instabilities even a few days before the event. Second, the ice avalanche was released very early in the season. Ice and debris with a volume of 300 000 m3 avalanched over a vertical distance of 1200 m. The main deposits with a volume of 250 000 m3 and a debris content of 10% formed a flat avalanche cone in the Käfer Valley covering 82 000 m2. This paper focuses on geomorphic and glaciological field measurements and observations at and below the ice avalanche deposit and its vicinity after the event. Studies were made (a) at the deposited material itself, (b) at the reshaped land surface below the deposit after ice melt, (c) at the front and margin of the deposit, and (d) outside the deposit. Our study reveals different types of ice-avalanche impact landforms comparable to landforms caused by snow avalanches. It is shown that ice avalanches charged with debris at the Nördliches Bockkarkees are important in forming and reshaping erosional and depositional landforms along the track. However, the conservation potential of these landforms is low. [ABSTRACT FROM AUTHOR]

Mergili, M., Kopf, C., Müllebner, B. and Schneider, J.F., 2012. Changes of the cryosphere and related geohazards in the high-mountain areas of Tajikistan and Austria: a comparison. Geografiska Annaler: Series A, Physical Geography, 93, 79-96. doi:10.1111/j.1468-0459.2011.00450.x ABSTRACT This paper quantifies recent glacier changes and possible future permafrost retreat in the Austrian Alps and the Pamir and Alai Mountains of Tajikistan (Central Asia), two mountainous areas with striking differences in climate and hypsometry, but also in economy and research history. The aim of the comparative study is to improve the understanding of regional differences as a baseline for further research and for a differentiated evaluation of possible socio-economic implications. Besides a review of the available literature, multi-temporal remote sensing of glaciers of selected areas as well as additional helicopter and field surveys were conducted. The Tajik glaciers displayed a differentiated behaviour during the investigation period 1968-2009, with a strong trend to retreat - at least since 2002. More than 100 pro- and supraglacial lakes have been forming or growing in the southwestern Pamir. Destructive outburst floods of such lakes have occurred there in the recent past. Almost all Austrian glaciers are in an advanced stage of retreat, a trend which continues at enhanced rates. Comparatively few glacial lakes exist in the direct forefields of the glaciers. Potential permafrost distribution maps for the present and the future were produced for Tajikistan and Austria by adapting an empirical model developed in Switzerland. In absolute terms, the highest loss was predicted for the Pamir. The expected relative loss in the same area is moderate compared to the rest of Tajikistan and particularly to Austria, where the model predicted the disappearance of more than 90% of the potential permafrost until the end of the twenty-first century. [ABSTRACT FROM AUTHOR]

Four different sites in the highlands of central Iceland have been investigated for permafrost occurrence using two-dimensional resistivity imaging. The results of the surveys indicate the presence of shallow permafrost of low to medium resistivity. The distribution pattern is spatially heterogeneous which is consistent with permafrost at the fringe of seasonal frost. These sites are likely to react rapidly to changes of the environmental boundary conditions, therefore future research should include monitoring for detecting the early impact of climate change on permafrost degradation. The extent to which periglacial morphodynamics and sediment fluxes are influenced by permafrost and/or seasonal frost and potential permafrost degradation is hard to determine. Hence, long-term monitoring approaches for both permafrost and sediment dynamics are essential. [ABSTRACT FROM AUTHOR]

Mountain landscapes show rapid evolution, especially at high altitudes, in response to current climate changes. In addition, the greater number of routes and trails made available and the increase in tourism have caused some impacts on mountain areas. Gradual soil erosion has been observed along some hiking trails, with the latter tending to deepen, and with stronger erosion where the trail cuts the slope. Where trails cross forested areas, trees can suffer root damage from foot trampling as roots become exposed. A dendrogeomorphological study was conducted on trees along two hiking trails in upper Valtellina (Italian Alps). On the first trail, in Valle dei Forni, European larches and stone pines, mostly with exposed roots, were sampled. A mean erosion rate of 2.7 mm/a, related to deepening of the footpath, was obtained, and various degrees of root growth disturbance along the trail were observed. In particular, the growth of many sampled roots shows an increase in ring width corresponding with the moment when root exposure occurred, followed, after 3-5 years, by rapid growth suppression. The exposure of many roots has taken place since the 1980s. No significant variations in stem growth were observed, even when there were exposed and damaged roots. Along the second trail, in Valle Alpisella, exposed roots of mountain pines were analysed. A mean erosion rate of 3.2-3.7 mm/a, related to the escarpments bordering the footpath, was obtained, while no significant changes were detected in root growth. [ABSTRACT FROM AUTHOR]

Small glaciers have short response times to climate change and therefore offer a powerful means of climate monitoring. Glacier responses to climate, or their mass change, may be suggested by a change in the Equilibrium Line Altitude (ELA). However, regional climatic reconstructions have repeatedly neglected the importance of local variations in ELAs in preference for regional trends. For small glaciers close to the glaciation level, ignoring the importance of local topographic components in mass balance estimates may lead to erroneous climatic reconstructions. Of 510 small valley and cirque glaciers digitised across northern Scandinavia, 284 were objectively deemed suitable for inferring an ELA. The inferred ELA was derived from the median elevation and several local topographic variables using regression analysis. The glacier elevation, area, slope and aspect parameters were found to be the best predictors of the local ELA. ELA estimations improved from 77% up to 94% accuracy when topographic parameters for every grid-cell within rasters representing glacier surfaces were computed rather than using subjective measurements from topographic maps. Regional ELA trend surfaces, interpolated between the local ELA values, differed in effectively representing the local variability, depending upon the distribution and accuracy of the local ELA values. A second-order polynomial trend surface most accurately represented ELA variations across the study area, within the initial local measurement accuracy of ±100 m. It is concluded that current subjective topographic mapbased analyses are unlikely to be sufficiently accurate for predicting the regional ELA of small, sensitive and marginal glaciers, unless GIS-based spatial analyses are made at a reasonable resolution. [ABSTRACT FROM AUTHOR]