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Abstract. Process interactions and chain reactions, the present shift of cryospheric hazard zones due to atmospheric warming, and the potential far reach of glacier disasters make it necessary to apply modern remote sensing techniques for the assessment of glacier and permafrost hazards in highmountains. Typically, related hazard source areas are situated in remote regions, often difficult to access for physical and/or political reasons. In this contribution we provide an overview of air-and spaceborne remote sensing methods suitable for glacier and permafrost hazard assessment and disaster management. A number of image classification and change detection techniques support high-mountain hazard studies. Digital terrain models (DTMs), derived from optical stereo data, synthetic aperture radar or laserscanning, represent one of the most important data sets for investigating high-mountain processes. Fusion of satellite stereo-derived DTMs with the DTM from the Shuttle Radar Topography Mission (SRTM) is a promising way to combine the advantages of both technologies. Large changes in terrain volume such as from avalanche deposits can indeed be measured even by repeat satellite DTMs. Multitemporal data can be used to derive surface displacements on glaciers, permafrost and landslides. Combining DTMs, results from spectral image classification, and multitemporal data from change detection and displacement measurements significantly improves the detection of hazard potentials. Modelling of hazardous processes based on geographic information systems (GIS) complements the remote sensing analyses towards an integrated assessment of glacier and permafrost hazards in mountains. Major present limitations in the application of remote sensing to glacier and permafrost hazards in mountains are, on the one hand, of technical nature (e.g. combination and fusion of different methods and data; improved unCorrespondence to: A. Kääb (kaeaeb@geo.unizh.ch) derstanding of microwave backscatter). On the other hand, better dissemination of remote sensing expertise towards institutions involved in high-mountain hazard assessment and management is needed in order to exploit the large potential of remote sensing in this field.

The rock‐ice avalanche that occurred in 2005 on Mount Steller, Alaska and the resulting long period seismic waves have been simulated for different avalanche scenarios (i.e., flow histories), with and without erosion processes taken into account. This 40–60 Mm3avalanche traveled about 10 km down the slope, mainly on top of a glacier, eroding a significant amount of ice. It was recorded by 7 broadband seismic stations. The simulations were compared with the recorded long period seismic signal and with the inverted flow history. The results show that, when erosion processes are taken into account, the simulations reproduce the observed signal at all the stations over a wide range of azimuths and source‐station distances (37–623 km). This comparison makes it possible to constrain the rheological parameters involved which should help constrain the volume of eroded material. Because landslides are continuously recorded by seismic networks, this method could significantly broaden quantitative insights into natural flow dynamics.

[1] Rock-ice avalanches larger than 1 × 10 6 m 3 are high-magnitude, low-frequency events that may occur in all ice-covered, high mountain areas around the world and can cause extensive damage if they reach populated regions. The temporal and spatial evolution of the seismic signature from two events was analyzed, and recordings at selected stations were compared to numerical model results of avalanche propagation. The first event is a rock-ice avalanche from Iliamna volcano in Alaska which serves as a "natural laboratory" with simple geometric conditions. The second one originated on Aoraki/Mt. Cook, New Zealand Southern Alps, and is characterized by a much more complex topography. A dynamic numerical model was used to calculate total avalanche momentum, total kinetic energy, and total frictional work rate, among other parameters. These three parameters correlate with characteristics of the seismic signature such as duration and signal envelopes, while other parameters such as flow depths, flow path and deposition geometry are well in agreement with observations. The total frictional work rate shows the best correlation with the absolute seismic amplitude, suggesting that it may be used as an independent model evaluation criterion and in certain cases as model calibration parameter. The good fit is likely because the total frictional work rate represents the avalanche's energy loss rate, part of which is captured by the seismometer. Deviations between corresponding calculated and measured parameters result from site and path effects which affect the recorded seismic signal or indicate deficiencies of the numerical model. The seismic recordings contain additional information about when an avalanche reaches changes in topography along the runout path and enable more accurate velocity calculations. The new concept of direct comparison of seismic and avalanche modeling data helps to constrain the numerical model input parameters and to improve the understanding of (rock-ice) avalanche dynamics.Citation: Schneider, D., P. Bartelt, J. Caplan-Auerbach, M. Christen, C. Huggel, and B. W. McArdell (2010), Insights into rock-ice avalanche dynamics by combined analysis of seismic recordings and a numerical avalanche model, J. Geophys. Res., 115, F04026,

Abstract. Recent warming has had enormous impacts on glaciers and high-mountain environments. Hazards have changed or new ones have emerged, including those from glacier lakes that form as glaciers retreat. The Andes of Peru have repeatedly been severely impacted by glacier lake outburst floods in the past. An important recent event occurred in the Cordillera Blanca in 2010 when an ice avalanche impacted a glacier lake and triggered an outburst flood that affected the downstream communities and city of Carhuaz. In this study we evaluate how such complex cascades of mass movement processes can be simulated coupling different physically-based numerical models. We furthermore develop an approach that allows us to elaborate corresponding hazard maps according to existing guidelines for debris flows and based on modelling results and field work.

Large rock-ice avalanches have attracted attention from scientists for decades and some of these events have caused high numbers of fatalities. A relation between rock slope instabilities in cold high mountain areas and climate change is currently becoming more evident and questions about possible consequences and hazard scenarios in densely populated high mountain regions leading beyond historical precedence are rising. To improve hazard assessment of potential rock-ice avalanches, their mobility is a critical factor. This contribution is an attempt to unravel driving factors for the mobility of large rock-ice avalanches by synthesizing results from physical laboratory experiments and empirical data from 64 rock-ice avalanches with volumes >1x10 6 m 3 from glacierized high mountain regions around the world. The influence of avalanche volume, water and ice content, low-friction surfaces, and topography on the apparent coefficient of friction (as a measure of mobility) is assessed. In laboratory experiments granular ice in the moving mass was found to reduce bulk friction up to 20% while water led to a reduction around 50% for completely saturated material compared with dry flows. Evidence for the effects of water as a key driving factor to enhance mobility was also found in the empirical data, while the influence of the ice content could not be confirmed to be of much relevance in nature. Besides liquefaction, it was confirmed that mobility increases with volumes and that frictional surface characteristics such as flow paths over glaciers are also dominant variables determining mass movement mobility. Effects of the topography along the flow path as well as channeling are assumed to be other critical factors. The results provide an empirical basis to roughly account for different path and flow characteristics of large rock-ice avalanches and to find appropriate ranges for friction parameters for scenario modeling and hazard assessments.

The number of large slope failures in some high-mountain regions such as the European Alps has increased during the past two to three decades. There is concern that recent climate change is driving this increase in slope failures, thus possibly further exacerbating the hazard in the future. Although the effects of a gradual temperature rise on glaciers and permafrost have been extensively studied, the impacts of short-term, unusually warm temperature increases on slope stability in high mountains remain largely unexplored.We describe several large slope failures in rock and ice in recent years in Alaska, New Zealand and the European Alps, and analyse weather patterns in the days and weeks before the failures. Although we did not find one general temperature pattern, all the failures were preceded by unusually warm periods; some happened immediately after temperatures suddenly dropped to freezing.We assessed the frequency of warm extremes in the future by analysing eight regional climate models from the recently completed European Union programme ENSEMBLES for the central Swiss Alps. The models show an increase in the higher frequency of high-temperature events for the period 2001-2050 compared with a 1951-2000 reference period. Warm events lasting 5, 10 and 30 days are projected to increase by about 1.5-4 times by 2050 and in some models by up to 10 times.Warm extremes can trigger large landslides in temperature-sensitive high mountains by enhancing the production of water by melt of snow and ice, and by rapid thaw. Although these processes reduce slope strength, they must be considered within the local geological, glaciological and topographic context of a slope.

When introduced species threaten native flora and fauna, protection requires an analysis of the risk that native species face from the spread of the introduced species. Models of invading species, however, often do not include a dynamic component of risk. North American freshwater mussels are at risk of fouling by the introduced zebra mussel ( Dreissena polymorpha ). Predictions of the risk to native mussel communities of invasion by the zebra mussel can help prioritize conservation efforts. We present a model for the spatial analysis of zebra mussel spread that allows the characterization of relative risk of infestation to the high-quality mussel communities of Illinois streams. A gravity model, constrained at origin and destination, was parameterized with data on boat use at 120 boat landings in Illinois. The risk of spread of zebra mussels depends on the number of boat trips from infested waters, which in turn depends on distance from an infested water, boat use at a site, and the position of a lake within a river system. Habitats supporting a high diversity of native mussels and threatened and endangered species are at risk of infestation from reservoirs upstream. Invasion of inland lakes and reservoirs in Illinois is predicted to occur first at areas of high boat use close to currently infested waters, including the Fox Chain of Lakes, followed by central Illinois reservoirs. These reservoirs will act as stepping stones, facilitating the invasion of lakes upstream of critical native mussel habitats. Efforts to protect waters that center on prevention of the initial invasion of stepping-stone lakes could significantly reduce the risk of infestation. Education and inspection efforts are predicted to be more effective than quarantine because quarantines would displace boat traffic to critical habitats. The class of models presented here is useful for predicting risk of invasion when complete data on vector movement are not available.Evaluación de Riesgo de un Modelo de Transportación para Comunidades Nativas de Mejillones Debido a la Dispersión del Mejillon Zebra Resumen: Cuando las especies introducidas amenazan la flora y fauna nativa, la protecci ó n requiere de un análisis del riesgo que las especies nativas enfrentan debido a la disperción de las especies introducidas. Sin embargo, los modelos de invasi ó n de especies frecuentemente no incluyen un componente dinámico de riesgo. Los mejillones de Norteamérica se encuentran en riesgo de ser entampados por el mejill ó n zebra introducido ( Dreissena polymorpha ). Las predicciones de riesgo para las comunidades nativas de mejillones podrían ayudar a priorizar los efuerzos de conservación. Presentamos un modelo de análisis espacial de la dispersión del mejillón zebra que permite la caracterización del riesgo relativo de infestación de comunidades de mejillones de alta calidad de los arrollos de Illinois. Un modelo de gravedad, forzado en el origen y destino, se parametrizó con datos de uso de botes en 120 arribos en Illinois. El riesgo de dispersión del mejill...