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1.
The physical risk from snow avalanches poses a serious threat to mountain backcountry travelers. Avalanche risk is primarily managed by (1) assessing avalanche hazard through analysis of the local weather, snowpack, and recent avalanche activity and (2) selecting terrain that limits exposure to the identified hazard. Professional ski guides have a tremendous wealth of knowledge about using terrain to manage avalanche risk, but their expertise is tacit, which makes it difficult for them to explicitly articulate the underlying decision rules. To make this existing expertise more broadly accessible, this study examines whether it is possible to derive quantitative measures for avalanche terrain severity and condition-dependent terrain guidance directly from observed terrain selection of professional guides. We equipped lead guides at Mike Wiegele Helicopter Skiing with GPS tracking units during the 2014/2015 and 2015/2016 winters creating a dataset of 10,592 high-resolution tracked ski runs. We used four characteristics—incline, vegetation, down-slope curvature (convexities/concavities), and cross-slope curvature (gullies/ridges)—to describe the skied terrain and employed a mixed-effects ordered logistic regression model to examine the relationship between the character of most severe avalanche terrain skied on a day and the associated field-validated avalanche hazard ratings. Patterns in the regression parameter estimates reflected the existing understanding of how terrain is selected to manage avalanche risk well: the guides skied steeper, less dense vegetation, and more convoluted slopes during times of lower avalanche hazard. Avalanche terrain severity scores derived from the parameter estimates compared well to terrain previously zoned according to the Avalanche Terrain Exposure Scale. Using a GIS implementation of the regression analysis, we created avalanche condition-dependent maps that provide insights into what type of terrain guides deemed acceptable for skiing under different avalanche hazard conditions. These promising results highlight the potential of tracking guides’ terrain selection decisions as they manage avalanche hazard for the development of evidence-based avalanche terrain ratings and decision aids for professional and recreational backcountry travelers. 相似文献
2.
Christian Pfeifer 《Natural Hazards》2009,48(3):425-438
Most fatal avalanche accidents in the Alps are caused by skiers and snowboarders. It has been one aim from the beginning to
give guidelines for backcountry skiers in order to avoid avalanche accidents. About 10 years ago, the mountain guide Werner
Munter developed a strategy for backcountry skiers whether to go or not to go on a skiing tour. However, his decision strategy
has a lack of empirical evidence because he does not take into account incidents without avalanche accidents. This article
proposes a decision strategy for backcountry skiers based on probabilities of a logistic regression model using variables,
such as danger level, incline of the slope and aspect of the slope, which turned out to be the most important ones. Additional
information on frequencies of skiers on slopes under specific conditions is included in the model. We used accident data and
avalanche forecasts in Tyrol reported by the Tyrolean avalanche information service within three seasons (1999–2002, 497 days
of observations) for model building. Additionally we carried out a holdout validation using data of the same type within two
seasons (2002–2004, 314 days of observation) in order to check the accuracy of the model. Our proposal shows a remarkable
correlation with Munter’s method. 相似文献
3.
Skier-triggered avalanches are the main cause of avalanche accidents in backcountry skiing. The risk of accidents during backcountry
skiing was analysed statistically and related to factors such as elevation level, aspect, stability rating and the time of
the year. The analysis is based on a database about terrain usage and avalanche accidents from a large heli-skiing operator
in Canada, which makes it possible to study the conditional probability of accidents given the recorded pattern of terrain
usage. This study shows that the historical risk of accidentally triggering an avalanche greater than size 1 depends highly
on the stability rating, with the highest risk occurring during “poor” stability. The risk is greater at high elevations,
and it is lower during the late season than earlier on. Skier risk does not depend as much on aspect as may be indicated from
avalanche data alone. However, it is relatively high in the N–NE–E sector. These factors are not independent of each other
and therefore analyses of combined factors were also performed. Questionnaires and interviews were used to gain knowledge
about the terrain selection of professional mountain guides. These results indicate that when selecting terrain, guides first
look at the overall shape and size of the terrain, but avalanche history of terrain and inclination are also important factors.
Finally, remarks in avalanche reports were analysed, and common human factors identified. 相似文献
4.
Avalanche impacts in Canada, including fatalities, are summarized for residential and public areas, as well as roads, ski areas, backcountry recreation, and resource industries. Methods for managing avalanche hazard, which include defence structures, zoning, forecasting and explosive control, are outlined. Problems with current avalanche hazard management are identified and progress at solving these problems is identified with an emphasis on residential areas, backcountry recreation and resource industries. 相似文献
5.
D. M. McClung 《Natural Hazards》2011,59(3):1635-1645
In North America and Europe, most fatalities due to snow avalanches occur in the backcountry during recreational pursuits.
Of these, more than 90% of the fatal avalanches are triggered by the victims themselves. This pattern suggests that the primary
cause of avalanche fatalities for human-triggered avalanches is a failure in human perception. For the latter, people thought
that the state of stability or instability of the snow cover was different than it actually was. In this paper, the strength
and weight of evidence used to make decisions in backcountry travel are discussed from: (a) the perspective of the favored
hypothesis to proceed for good recreational enjoyment based on stability evaluation and (b) the null hypothesis based on an
assessment of instability. Based on the facts about snow slab avalanche release, it is argued that instability analysis is
the best framework for avalanche forecasting, whereas human action is most closely related to the favored hypothesis (stability
evaluation). Using scaling laws derived from: (a) fracture mechanics about the size of imperfections causing avalanches and
(b) avalanche dimensions, it is suggested that a snow slab could show stability over more than 99% of the total area. From
the concepts of Bayesian probability, it is shown that overconfidence about stability can arise when the weight of the likelihood
is high and the weight of prior is low. Similarly, underconfidence (excessive conservatism) often results when the weight
of the prior is high with little regard for the likelihood, which may be low. Overconfidence about stability is considered
to be a prime source of accidents. 相似文献
6.
Grant Statham Pascal Haegeli Ethan Greene Karl Birkeland Clair Israelson Bruce Tremper Chris Stethem Bruce McMahon Brad White John Kelly 《Natural Hazards》2018,90(2):663-691
This conceptual model of avalanche hazard identifies the key components of avalanche hazard and structures them into a systematic, consistent workflow for hazard and risk assessments. The method is applicable to all types of avalanche forecasting operations, and the underlying principles can be applied at any scale in space or time. The concept of an avalanche problem is introduced, describing how different types of avalanche problems directly influence the assessment and management of the risk. Four sequential questions are shown to structure the assessment of avalanche hazard, namely: (1) What type of avalanche problem(s) exists? (2) Where are these problems located in the terrain? (3) How likely is it that an avalanche will occur? and (4) How big will the avalanche be? Our objective was to develop an underpinning for qualitative hazard and risk assessments and address this knowledge gap in the avalanche forecasting literature. We used judgmental decomposition to elicit the avalanche forecasting process from forecasters and then described it within a risk-based framework that is consistent with other natural hazards disciplines. 相似文献
7.
Avalanche hazard and risk mapping is of utmost importance in mountain areas in Europe and elsewhere. Advanced methods have been developed to describe several aspects of avalanche hazard assessment, such as the dynamics of snow avalanches or the intensity of snowfall to assume as a reference meteorological forcing. However, relatively little research has been conducted on the identification of potential avalanche release areas. In this paper, we present a probabilistic assessment of potential avalanche release areas in the Italian Autonomous Province of Bolzano, eastern Alps, using the Weights of Evidence and Logistic Regression methods with commonly available GIS datasets. We show that a data-driven statistical model performs better than simple, although widely adopted, screening criteria that were proposed in the past, although the complexity of observed release areas is only partly captured by the model. In the best case, the model enables predicting about 70 % of avalanches in the 20 % of area classified at highest hazard. Based on our results, we suggest that probabilistic identification of potential release areas could provide a useful aid in the screening of sites for subsequent, more detailed hazard assessment. 相似文献
8.
This paper (Part II) constitutes the second of a two part series todefine the seven elements of avalanche forecasting. Part I contains the first four elements which are neededto present the human issues. This paper contains the last three elements which deal mostly with thephysical issues and their use in the decision-making process. Some basic rules of applied avalancheforecasting are included here, for the first time, to illustrate physically based principleswhich are used in applied avalanche forecasting and their link to data analysis and decisions.Since the seven elements of applied avalanche forecasting are strongly connected, the reader should consultPart I (this journal issue) as a prelude to the present paper. Part II contains sections about dataand information, scale issues in time and space, decision making and errors and physical rules ofapplied forecasting. Since all seven elements of applied avalanche forecasting are connected, Part II does not stand alone. 相似文献
9.
M. A. Hamadouche K. Mederbal L. Kouri Z. Regagba Y. Fekir D. Anteur 《Arabian Journal of Geosciences》2014,7(2):419-434
This paper presents a geographic information system (GIS)-based multicriteria decision-making approach for biodiversity preservation of the Ahaggar National Park in Algeria. This tool named spatial decision-making aid (SDMA) enables decision makers to evaluate the relative priorities of conserving the biodiversity in protected areas basing on a set of preferences, criteria and indicators of the area. In this study, we have developed conceptual and methodological solutions to integrate outranking methods (such as elimination and choice to translate reality TRI, preference ranking organizational methods and analytical hierarchy process) of multicriteria analysis in the GIS software to enhance its potential as tools of spatial decision support in land management problems. We integrated the results and other data relevant studied area in a GIS as a starting point for our SDMA prototype for resources management. Through the application, we have designed functionalities that allow producing maps of areas which needed urgent preservation. These methods are more appropriate to decision-making problems and their integration into GIS software (ArcView GIS 3.2 software from Environmental Systems Research Institute) that constitutes a powerful tool of spatial decision-making aid. 相似文献
10.
滑坡灾害分析是系统性工程,不仅需要准确反映其现状动态特征,而且还应体现其安全稳定状况,为工程治理提供可靠依据。以GIS和Surfer为基础平台,有效耦合各项功能模块,开发出滑坡灾害综合评判决策系统,实现其现状动态分析、变化规律预测及稳定特性研究。详细阐述了系统的体系结构、总体设计、开发基础、功能模块集成,着重研究了系统功能实现的应用方面,包括地形信息处理、虚拟地景可视化、综合决策分析、变形预测预报和稳定性数值分析,分别对其功能内容、理论基础和应用流程进行具体分析。针对滑坡工程治理的效果评价问题,采用系统模糊马尔科夫链模型予以决策分析,在详细阐述其理论结构的基础上引入工程实例进行具体研究。结果表明：滑坡治理效果较好,模型分析客观地反映了其目前所处的安全稳定状态。综上可见,该系统可为滑坡灾害分析与工程治理实现信息化、动态化、决策化提供可行的技术平台。 相似文献
11.
This paper presents an assessment of the avalanche hazard potential and the resulting risks on mountain roads for a 38.7-km-long
section of road no 76 (Siglufjarearvegur) in northern Iceland following a regional scale approach developed in the Alps. The
assessment of the individual avalanche death risk proved applicable to distinguish areas of avalanche hazard with a risk above
the accepted level, which should be given priority in following detailed investigations and the planning of possible protective
measures, from road sections where the avalanche death risk is low and accepted according to international practice. The cumulative
individual and collective avalanche death risks in the investigated road section provide a comparable measure for assessing
the avalanche hazard both within the Icelandic public road network and on an international scale. The case study on road no
76 in northern Iceland shows that a standardised regional scale risk-based approach is practical to determine, analyse and
assess the avalanche hazard situation on mountain roads in Iceland and guarantees comprehensible, reproducible and comparable
results as a basis for a sustainable planning of measures. 相似文献
12.
Avalanche warning services (AWS) are operated to protect communities and traffic lines in avalanche-prone regions of the Alps and other mountain ranges. In times of high avalanche danger, these services may decide to close roads or to evacuate settlements. Closing decisions are based on field observations, avalanche release statistics, and snow forecasts issued by weather services. Because of the spatial variability in the snowpack and the insufficient understanding of avalanche triggering mechanisms, closing decisions are characterized by large uncertainties and the information based on which AWS have to decide is always incomplete. In this paper, we illustrate how signal detection theory can be applied to make better use of the information at hand. The proposed framework allows the evaluation of past road closures and points to how the decision performance of AWS could be improved. To illustrate the proposed framework, we evaluate the decision performance of two AWS in Switzerland and discuss the advantages of such a formalized decision-making approach. 相似文献
13.
Reported avalanche fatalities in the United States increased markedly through the latter half of the twentieth century, a
result of the increasing popularity of winter sports. Despite this increase, the literature concerning US avalanche fatalities
is sparse. This paper presents a comparison of three US databases containing avalanche fatality information: Storm Data, the West Wide Avalanche Network (WWAN) dataset, and the National Avalanche Database (NAD). The frequency of avalanche fatalities,
their temporal trends, spatial distributions, and the demographic characteristics of the victims were analyzed in each database
for the years 1998–2009 for the US mountainous west. The data were then pooled to arrive at an estimate of avalanche fatality
frequency in the United States for the study period. While the results indicate a considerable amount of overlap between the
datasets, Storm Data reports fewer avalanche fatalities than both the WWAN and NAD datasets. All three datasets report a maximum of fatalities
in January and display three spatial maxima: the Rocky Mountains of west-central Colorado, the intermountain region from central
Utah through Idaho to west-central Montana, and the northern Cascade Ranges of Washington; however, a large void appears in
the Storm Data records in the vicinity of the Montana maximum. These maxima result from a juxtaposition of avalanche hazard in these mountainous
environments with a high concentration of winter sports activities. 相似文献
14.
梅里雪山雪崩多发,但缺乏系统监测和研究。1991年1月3日梅里雪山发生了造成中日联合登山队17名队员遇难的巨大雪崩事件。2019年安装在明永冰川末端附近的物候相机拍摄到临近梅里雪山明永冰川的一次雪崩事件。两次事件类型不同,这对我们进行雪崩预测预警有良好的指示作用。本研究以RAMMS(Rapid Mass Movement System)模型为手段,利用经验值和经验公式确定影响模拟结果的主要模型参数和积雪可能断裂深度,在优化分析的基础上,对两次雪崩事件进行重建,定量分析雪崩堆积量、堆积范围等。结果显示:1991年雪崩共持续了192s,雪崩体从海拔5730m处断裂,沿坡面崩塌而下最终堆积在海拔约5000m的冰川粒雪盆地区,形成面积为0.6km^(2),体积约67×10^(4)m^(3)的堆积体。2019年雪崩共持续了158s,雪崩流最大高度35.91m,最大速度79.34m·s,堆积量76.2×10^(4)m^(3),雪崩堆积范围与野外观测到的一致。两次雪崩事件发生地位于雪崩极高危险区和高危险区,在一定程度上验证了风险评估的准确性。研究结果可为梅里雪山地区未来潜在雪崩灾害的风险评估提供依据,为雪崩预测预警提供良好的参考。 相似文献
15.
Sally Eden 《Geoforum》2012,43(5):1014-1023
This paper examines how environmental resources are measured and quantified as objects of environmental science and management and how lay knowledge-producers participate in this process, alongside the state. Using a case study of recreational angling, I show how fish in English rivers and lakes are counted and anglers act as lay or amateur knowledge-producers in the state’s metrological knowledge-practices. As embodied measurement instruments, anglers create data about themselves (as ‘effort data’) and about fish (as ‘catch returns’). These data are combined with other forms of data produced by the Environment Agency in England and Wales and used for fisheries management, thus shaping water bodies and fish ecology. I show how, to support environmental measurement, the state manages not only the environment and fish, but also anglers as lay knowledge-producers, using both regulation and economic incentives; in response, anglers also use data reflexively and strategically. I therefore emphasise the heterogeneous co-productions of environmental measurement as amateur–professional, human–animal and organic–technological, and show how measuring and managing water ecologies also involves measuring and managing humans. 相似文献
16.
The prehistoric Mt Wilberg rock avalanche, Westland, New Zealand 总被引：1，自引：0，他引：1
The Mt Wilberg rock avalanche in Westland, New Zealand occurred before 1300 AD and may have occurred as a consequence of an
Alpine fault earthquake in ca. 1220 AD or earlier. Its ∼40 × 106 m3 deposit may have briefly obstructed the Wanganui River, but only about 25% of its surface morphology still survives, on terraces
isolated from river erosion. The landslide appears to have moved initially as a block, in a direction controlled by a strong
rock mass at the base of the source area, before disintegrating and spreading across terraces, fans, and floodplains. Rock
avalanche deposits in Westland have relatively short expected lifetimes in the rugged terrain and high rainfall of the area;
hence, the hazard from such events is under-represented by their current remnants. 相似文献
17.
Snow avalanches are a major natural hazard for road users and infrastructure in northern Gaspésie. Over the past 11 years, the occurrence of nearly 500 snow avalanches on the two major roads servicing the area was reported. No management program is currently operational. In this study, we analyze the weather patterns promoting snow avalanche initiation and use logistic regression (LR) to calculate the probability of avalanche occurrence on a daily basis. We then test the best LR models over the 2012–2013 season in an operational forecasting perspective: Each day, the probability of occurrence (0–100%) determined by the model was classified into five classes avalanche danger scale. Our results show that avalanche occurrence along the coast is best predicted by 2 days of accrued snowfall [in water equivalent (WE)], daily rainfall, and wind speed. In the valley, the most significant predictive variables are 3 days of accrued snowfall (WE), daily rainfall, and the preceding 2 days of thermal amplitude. The large scree slopes located along the coast and exposed to strong winds tend to be more reactive to direct snow accumulation than the inner-valley slopes. Therefore, the probability of avalanche occurrence increases rapidly during a snowfall. The slopes located in the valley are less responsive to snow loading. The LR models developed prove to be an efficient tool to forecast days with high levels of snow avalanche activity. Finally, we discuss how road maintenance managers can use this forecasting tool to improve decision making and risk rendering on a daily basis. 相似文献
18.
19.
Snow avalanches are a significant hazard in mountainous environments around the world. This paper investigates the major February 1986 avalanche cycle that occurred in the western United States, and broadly analyzes the avalanche, snowpack, and weather conditions at twenty sites. These analyses suggest that the avalanche cycle resulted from the interaction of a relatively `normal' snowpack with an exceptional storm event, which was particularly noteworthy for the amount of precipitation it produced. Composited 500-hPa anomaly maps show the event resulted from an uncommonly persistent blocking pattern that resulted in a strong zonal flow and copious moisture being funneled over the western United States. Understanding severe and widespread avalanche cycles may improve our long-term forecasting of these events, and help mitigate theresulting avalanche activity. 相似文献
20.
N. C. Barth 《Landslides》2014,11(3):327-341
Catastrophic deep-seated rock slope failures (RSFs; e.g., rock avalanches) can be particularly useful proxies for fault rupture and strong ground motion, and currently represent an underappreciated hazard of earthquakes in New Zealand. This study presents observations of the previously undescribed Cascade rock avalanche (CRA), a c. 0.75 km3 single-event, long-runout, catastrophic failure interpreted to have been coseismically triggered by a large to great earthquake c. 660 AD on the Alpine Fault. Despite its size and remarkable preservation, the CRA deposit has been previously identified as a terminal moraine and fault-damaged outcrop, highlighting the common misinterpretation of similar rock avalanche deposits. Comparisons are drawn between the CRA and other Alpine Fault-attributed rock avalanches, such as the better-studied c. 860 AD Round Top rock avalanche, to re-assess coseismic rock avalanche hazard. Structural relationships indicate the rock mass comprising the CRA may have formerly been a portion of a larger (c. 3 km3) RSF, before its catastrophic collapse on a deep-seated gravitational collapse structure (sackung). Sackungen and RSFs are common throughout the Southern Alps and other mountainous regions worldwide; in many cases, they should be considered potential precursors to catastrophic failure events. Two masses of rock in the Cascade River Valley show precursory signs of potential catastrophic failures of up to c. 2 km3; a similar mass may threaten the town of Franz Josef. 相似文献