Avalanche related damage potential - changes of persons and mobile values since the mid-twentieth century, case study Galtür

When determining risk related to natural hazard processes, many studies neglect the investigations of the damage potential or are limited to the assessment of immobile values like buildings. However, persons as well as mobile values form an essential part of the damage potential. Knowledge of the maximum number of exposed persons in an endangered area is of great importance for elaborating evacuation plans and immediate measures in case of catastrophes. In addition, motor vehicles can also be highly damaged, as was shown by the analysis of avalanche events. With the removal of mobile values in time as a preventive measure this kind of damage can be minimised. <P style='line-height: 20px;'> This study presents a method for recording the maximum number of exposed persons and monetarily assessing motor vehicles in the municipality of Galt&#252;r (Tyrol, Austria). Moreover, general developments of the damage potential due to significant socio-economic changes since the mid-twentieth century are pointed out in the study area. The present situation of the maximum number of persons and mobile values in the official avalanche hazard zones of the municipality is described in detail. Information on the number of persons is derived of census data, tourism and employment statistics. During the winter months, a significant increase overlaid by strong short-term fluctuation in the number of persons can be noted. These changes result from a higher demand of tourism related manpower as well as from varying occupancy rates. The number of motor vehicles in endangered areas is closely associated to the number of exposed persons. The potential number of motor vehicles is investigated by means of mapping, statistics on the stock of motor vehicles and the density distribution. Diurnal and seasonal fluctuations of the investigated damage potential are pointed out. The recording of the number of persons and mobile values in endangered areas is vital for any disaster management

Temporal variability of damage potential on roads as a conceptual contribution towards a short-term avalanche risk simulation

The fatality risk caused by avalanches on road networks can be analysed using a long-term approach, resulting in a mean value of risk, and with emphasis on short-term fluctuations due to the temporal variability of both, the hazard potential and the damage potential. In this study, the approach for analysing the long-term fatality risk has been adapted by modelling the highly variable short-term risk. The emphasis was on the temporal variability of the damage potential and the related risk peaks. For defined hazard scenarios resulting from classified amounts of snow accumulation, the fatality risk was calculated by modelling the hazard potential and observing the traffic volume. The avalanche occurrence probability was calculated using a statistical relationship between new snow height and observed avalanche releases. The number of persons at risk was determined from the recorded traffic density. The method resulted in a value for the fatality risk within the observed time frame for the studied road segment. The long-term fatality risk due to snow avalanches as well as the short-term fatality risk was compared to the average fatality risk due to traffic accidents. The application of the method had shown that the long-term avalanche risk is lower than the fatality risk due to traffic accidents. The analyses of short-term avalanche-induced fatality risk provided risk peaks that were 50 times higher than the statistical accident risk. Apart from situations with high hazard level and high traffic density, risk peaks result from both, a high hazard level combined with a low traffic density and a high traffic density combined with a low hazard level. This provided evidence for the importance of the temporal variability of the damage potential for risk simulations on road networks. The assumed dependence of the risk calculation on the sum of precipitation within three days is a simplified model. Thus, further research is needed for an improved determination of the diurnal avalanche probability. Nevertheless, the presented approach may contribute as a conceptual step towards a risk-based decision-making in risk management

Effects of variability in probable maximum precipitation patterns on flood losses

The assessment of the impacts of extreme floods is important for dealing with residual risk, particularly for critical infrastructure management and for insurance purposes. Thus, modelling of the probable maximum flood (PMF) from probable maximum precipitation (PMP) by coupling hydrological and hydraulic models has gained interest in recent years. Herein, we examine whether variability in precipitation patterns exceeds or is below selected uncertainty factors in flood loss estimation and if the flood losses within a river basin are related to the probable maximum discharge at the basin outlet. We developed a model experiment with an ensemble of probable maximum precipitation scenarios created by Monte Carlo simulations. For each rainfall pattern, we computed the flood losses with a model chain and benchmarked the effects of variability in rainfall distribution with other model uncertainties. The results show that flood losses vary considerably within the river basin and depend on the timing and superimposition of the flood peaks from the basin's sub-catchments. In addition to the flood hazard component, the other components of flood risk, exposure, and vulnerability contribute remarkably to the overall variability. This leads to the conclusion that the estimation of the probable maximum expectable flood losses in a river basin should not be based exclusively on the PMF. Consequently, the basin-specific sensitivities to different precipitation patterns and the spatial organization of the settlements within the river basin need to be considered in the analyses of probable maximum flood losses

Blended Learning in ESP Methodology: WebQuest

The paper focuses on key issues of blended learning and introduces the idea of WebQuest and the adaptation of this approach in teaching ESP.Статья посвящена основным вопросам смешанного обучения (blended learning) и рассматривает возможности использования образовательной технологии WebQuest при обучении английскому языку профессионального общения

Modelling woody material transport and deposition in alpine rivers

Recent flood events in Switzerland and Western Austria in 2005 were characterised by an increase in impacts and associated losses due to the transport of woody material. As a consequence, protection measures and bridges suffered considerable damages. Furthermore, cross-sectional obstructions due to woody material entrapment caused unexpected flood plain inundations resulting in severe damage to elements at risk. Until now, the transport of woody material is neither sufficiently taken into account nor systematically considered, leading to prediction inaccuracies during the procedure of hazard mapping. To close this gap, we propose a modelling approach that (1) allows the estimation of woody material recruitment from wood-covered banks and flood plains; (2) allows the evaluation of the disposition for woody material entrainment and transport to selected critical configurations along the stream and that (3) enables the delineation of hazard process patterns at these critical configurations. Results from a case study suggest the general applicability of the concept. This contribution to woody material transport analysis refines flood hazard assessments due to the consideration of woody material transport scenarios

Hazard index maps for woody material recruitment and transport in alpine catchments

A robust and reliable risk assessment procedure for hydrologic hazards deserves particular attention to the role of transported woody material during flash floods or debris flows. At present, woody material transport phenomena are not systematically considered within the procedures for the elaboration of hazard maps. The consequence is a risk of losing prediction accuracy and of underestimating hazard impacts. Transported woody material frequently interferes with the sediment regulation capacity of open check dams and moreover, when obstruction phenomena at critical crosssections of the stream occur, inundations can be triggered. The paper presents a procedure for the determination of the relative propensity of mountain streams to the entrainment and delivery of recruited woody material on the basis of empirical indicators. The procedure provided the basis for the elaboration of a hazard index map for all torrent catchments of the Autonomous Province of Bolzano/Bozen. The plausibility of the results has been thoroughly checked by a backward oriented analysis on natural hazard events, documented since 1998 at the Department of Hydraulic Engineering of the aforementioned Alpine Province. The procedure provides hints for the consideration of the effects, induced by woody material transport, during the elaboration of hazard zone maps

Avalanche related damage potential - changes of persons and mobile values since the mid-twentieth century, case study Galtür

When determining risk related to natural hazard processes, many studies neglect the investigations of the damage potential or are limited to the assessment of immobile values like buildings. However, persons as well as mobile values form an essential part of the damage potential. Knowledge of the maximum number of exposed persons in an endangered area is of great importance for elaborating evacuation plans and immediate measures in case of catastrophes. In addition, motor vehicles can also be highly damaged, as was shown by the analysis of avalanche events. With the removal of mobile values in time as a preventive measure this kind of damage can be minimised. This study presents a method for recording the maximum number of exposed persons and monetarily assessing motor vehicles in the municipality of Galt¨ur (Tyrol, Austria). Moreover, general developments of the damage potential due to significant socio-economic changes since the mid-twentieth century are pointed out in the study area. The present situation of the maximum number of persons and mobile values in the official avalanche hazard zones of the municipality is described in detail. Information on the number of persons is derived of census data, tourism and employment statistics. During the winter months, a significant increase overlaid by strong short-term fluctuation in the number of persons can be noted. These changes result from a higher demand of tourism related manpower as well as from varying occupancy rates. The number of motor vehicles in endangered areas is closely associated to the number of exposed persons. The potential number of motor vehicles is investigated by means of mapping, statistics on the stock of motor vehicles and the density distribution. Diurnal and seasonal fluctuations of the investigated damage potential are pointed out. The recording of the number of persons and mobile values in endangered areas is vital for any disaster management