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FS 3.151

Mountain hazards: understanding the key risk drivers beyond climate change

Details

Full Title
FS 3.151: Mountain hazards: understanding the key risk drivers beyond climate change
Scheduled
TBA
Location
TBA
Convener
Sven Fuchs
Co-Conveners
Margreth Keiler, Maria Papathoma, Matthias Schlögl,
Assigned to Synthesis Workshop
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Thematic Focus
Adaptation, Hazards, Others
Keywords
Exposure, Vulnerability, Key risk driver, Mountain hazards

Description

Despite major efforts, losses from mountain hazards continue to increase. While climate change is increasing the frequency and intensity of many hazards, other factors such as changes in exposure and vulnerability are still poorly understood. This session will explore these factors and aim to assess key risk drivers beyond climate change. Exposure, a critical element of risk assessment, is likely to increase with the expansion of settlements and industrial activities. However, information on the spatio-temporal dynamics of exposure at different scales remains limited. To accurately quantify the evolving risk, these data need to be analysed together with the effectiveness of existing mitigation measures. This analysis will contribute to discussions on the impacts of climate change on exposed communities, particularly in the context of shared socio-economic pathways (SSPs). Another key objective is to understand the vulnerability of elements at risk in order to reduce future losses. Current models of vulnerability need to be further validated by empirical data, experiments and alternative assessment methods. The integration of observational data and additional dimensions of vulnerability, including institutional vulnerability, is also essential. We invite contributions that integrate exposure analysis, vulnerability assessment and adaptation strategies. The session will focus on interactions between landscape processes and human activities in mountain areas, promoting adaptive approaches to risk management. Contributions should aim to identify key risk drivers behind natural hazard losses through a comprehensive examination of risk components.

Submitted Abstracts

ID: 3.10591

Exploring the potential of seasonal predictions for winter hazard assessment – a glimpse into the near future

Sascha Bellaire
Mühlbacher, Gudrun

Abstract/Description

Numerical weather and climate predictions have improved significantly in recent years. This is mainly due to increased computational power and hence the ability to process more observations, include better physical parameterizations or increasing the horizontal as well as vertical resolution of used numerical weather and climate models. In general, one has to distinguish between short term weather prediction of a couple of days and long-term climate prediction for decades and even centuries. Similar to the numerical weather prediction the assessment of winter natural hazards requires an accurate nowcasting of the state of the snow cover in terms of stability, e.g., for avalanche warning or for snow loads on infrastructures. This is typically done by observers doing manual observations depending on the target, i.e. snow profiles and stability tests or measurements of the snow water equivalent (SWE). However, only by adding the information of a weather forecast to the current state a warning for the next day or days becomes possible. For climate predictions knowing the current state is of less importance and due to increased computational costs and a high demand on data storage future scenarios for snow are typically limited to simple question such as the future evolution of the snow extent. However, for short-term and mid-term planning of resources for warning purposes or even winter tourism local authorities would benefit from a prediction into the near future, i.e., a season or a couple of weeks or month. Seasonal forecast, i.e., forecast of a couple of months could bridge the gap between weather and climate timescales. In this study we explore the potential of coupling snow cover models with seasonal winter forecast for avalanche warning purposes as well as prediction of critical snow load events by using an ensemble of seasonal hindcasts of the last 20 winters. Note that by forcing snow cover models with data form atmospheric models there is no direct coupling and therefore no feedback between both models. Therefore, this pilot study shows also the benefits of fully coupled sophisticated snow cover models for a seamless prediction from weather to climate timescales.

ID: 3.10726

Wildfire risk in mountain areas: focusing on the vulnerability in the wildfire urban interface (WUI)

Sven Fuchs
Echtler, Pia; Schlögl, Matthias; Papathoma-Köhle, Maria

Abstract/Description

Wildfire is an emerging risk for parts of central and northern Europe, including the European Alps. This has been demonstrated through recent wildfire events in this region that challenged authorities and emergency services. Although large catastrophic events are still relatively rare, this is subject to change since climate change is going to increase the days of fire weather in the future. Managing the wildfire risk in the wildland-urban interface may be particularly challenging due to the low risk perception, the lack of experience of the affected communities and the lack of empirical data from past events. Nevertheless, focusing on vulnerability is certainly the key to disaster risk reduction in this respect. Vulnerability assessment indicates hotspots that require intervention in order to avoid negative consequences from natural hazards (in this case wildfire) and can support decision making and the effective allocation of resources. We present herein research results and tools from two projects, national (REVEAL) and European (FIREPRIME), focusing on the physical vulnerability of buildings (residential and industrial) and infrastructure to wildfire as well as the development of tools for prevention and preparedness for communities located in the WUI in mountain areas. In more detail, an indicator-based approach has been developed for the vulnerability assessment of different elements at risk and an application for mobile phones that can assist homeowners to make the right decisions in order to minimize potential damage to their building has been created. In both projects, stakeholders (authorities, firefighters, policy makers etc.) had a decisive role and were involved in the co-creation of methods and tools.

ID: 3.10747

Spatiotemporal assessment of multi-hazard exposure for buildings in Austria

Sven Fuchs
Echtler, Pia; Schlögl, Matthias

Abstract/Description

The study presents a nationwide, spatially explicit assessment of buildings and citizens exposed to riverine flooding, torrential flooding, snow avalanches, and multi-hazards in Austria. It combines two datasets: (a) hazard information from local-scale hazard maps, and (b) building stock data, including location, size, building category, construction period, and population register data to estimate the number of occupants for each building. The results challenge the assumption that exposure will inevitably increase due to population growth and rising property values. The study shows that exposure levels vary based on regional differences in building stock development. While some regions have seen growth above the national average, others have experienced slower growth. These variations are influenced by Austria’s diverse topography, economic activities, and development priorities. The temporal assessment of exposure reveals significant differences in the dynamics of exposure to various hazards in relation to the total building stock. The findings emphasize that exposure to hazards does not automatically follow population or asset growth trends. In conclusion, the property-based assessment proves to be an effective tool for nationwide exposure assessments. It provides a robust framework for identifying key non-climate risk drivers and offers valuable insights for operational risk management. These insights should inform the development of adaptive strategies to improve resilience in the face of climate change. The study highlights the importance of integrating such assessments into long-term planning and policy development to address complex hazard exposure and asset growth dynamics.

ID: 3.11079

Interactions of Debris Flows and In-Channel Protection Measures

Theo St. Pierre Ostrander
Kammerlander, Johannes; Gems, Bernhard

Abstract/Description

Debris flows are one of the most critical geomorphic modifiers in mountain regions, with potentially disastrous consequences when they occur in developed areas. They involve the gravitational movement of a solid-fluid mixture, with sediment distributed throughout the entire flow depth. When the debris flow channel has a gradient higher than 10%, energy dissipation structures are often installed to reduce the momentum of the debris flow and to stabilize the channel geometry. The Firschnitzbach in East Tyrol, Austria, is a debris flow-prone channel with a series of energy dissipation structures (bed sills) spaced throughout the channel passing through the village of Virgen, Austria. On 4 August 2012, intense rainfall occurred in the Firschnitzbach catchment which triggered two debris flow events, characterized by a series of surges that overtopped the channel and damaged adjacent structures. A series of hydraulic simulations were performed using the Flow 3D software to better understand the processes occurring in the channel, the surge-generating mechanisms and the effectiveness of the countermeasures. The simulations were defined by steady-state conditions, flood hydrographs, and rheological parameters for both, clear-water conditions and debris flows. The simulations provided reasonable results for the overall hydraulic situation and showed that the removal of the countermeasures increased the freeboard, which reduced the overtopping potential, but did not reveal the surge-triggering mechanisms. However, video footage of the event showed that the debris surges with intense sediment concentration periodically stalled, changing the channel geometry through a negative depositional gradient between the bed sills, or bankfull deposition of debris flow material in the channel. The debris flow instabilities that occurred in the Firschnitzbach were caused by the impact and the rapid displacement of the incoming surge into the deposited material of the previous surge, which was caused by the reduction in channel gradient due to the installed countermeasures. As a result, bed sills were removed near critical infrastructure to improve debris flow conveyance and reduce the potential for the unique countermeasure-debris flow interactions that occur in the stepped portion of the channel.

ID: 3.11453

Redefining potentially dangerous glacial lakes by integrating hazard mapping and downstream exposure data in Bhutan

Sonam Rinzin
Dunning, Stuart; Carr, Rachel; Sattar, Ashim

Abstract/Description

Glacial lakes in the high mountain regions across the world are growing in both numbers and areas. Many of these glacial lakes have produced glacial lake outburst floods some of which were devastating, resulting in numerous deaths and destructions in the downstream communities. Amidst increasing hazards from glacial lakes, settlements in vulnerable downstream area continue to expand, thereby exacerbating GLOF risk. Traditionally, the potentially dangerous glacial lakes were primarily defined based on the likelihood of producing GLOF using attributes such as topographic features surrounding the lakes. However, this approach of defining potentially dangerous glacial lake is incomplete as it does not provide any information about how glacial lake impact downstream settlement. To this end, this study redefined potentially dangerous glacial lakes in Bhutan based on hydrodynamic hazard mapping and downstream exposure data. As a result, we have produced a hazard map for all glacial lakes in Bhutan with an area greater than 0.05 km2 and which are within 1 km of the glacier terminus. Our result shows that approximately 20882 people, 2620 buildings, 270 km of road, 402 bridges and 169 hectares of farmland are exposed to GLOF in Bhutan. Thorthormi Tsho in Lunana, Punatsangchu basin is the most dangerous glacial lake. We also identified five other lakes as highly dangerous which are distributed across the Wangchu (2), Chamkharchu (2), and Punatsangchu (1) basins. Among downstream settlements, Chhoekhor Gewog in Bumthang was found to have the highest level of GLOF danger, followed by Bumthang town, Punakha town, and Lunana. Furthermore, nine additional gewogs and towns were classified as having a high level of GLOF danger. These findings highlight the urgent need to strengthen and expand the coverage of the early warning network to include all high GLOF danger gewogs and towns, thereby enhancing disaster preparedness and risk mitigation efforts. This study underscores the importance of integrating hydrodynamic hazard mapping and downstream exposure data to improve the accuracy of GLOF risk assessments and inform targeted mitigation strategies in vulnerable regions.

ID: 3.12535

Changing strategies in debris flow mitigation in the European Alps

Madlaina Juvalta
Keiler, Margreth; Gems, Bernhard

Abstract/Description

In mountainous regions, debris flows are among the most severe natural hazard processes and, as recent events have shown, they remain a major threat. Minimising the risks associated with debris flows is therefore still of great importance today. This interface between humans and natural hazard processes is not a new phenomenon. However, the way in which natural hazard processes are explained and understood, and the strategies used to protect lives, infrastructure and agricultural land from the impacts of natural hazard processes or to minimise such impacts, have changed throughout human history.

The history considered here begins with the first large-scale structural protection measures built around 150 years ago. Over time, different strategies for dealing with debris flows have evolved in response to technological developments, new transport and construction opportunities, and a growing understanding of natural hazard processes. In addition, the introduction of the first government regulations (Torrent Control Act) and the formation of new authorities responsible for torrent control were important developments in the management of debris flow events. Recent debris flow management strategies typically involve complex combinations of various debris flow mitigation measures including elements of planning, monitoring and early warning in addition to structural protection measures. The history presented concludes by answering questions about possible future trends showing an increasing importance of temporary mitigation measures, or on the current and future role of ageing structural protection measures within debris flow mitigation strategies.

Based on a literature review, key criteria for the development of natural hazard strategies (e.g., costs, maintenance of structural protection measures and technical possibilities) are identified and analysed, and the key findings are summarised in a timeline. Overall, this study provides a comprehensive overview of the changing and evolving approaches to debris flow management in European countries over the last 150 years.

ID: 3.12625

Enabling and limiting factors for the effectiveness of protective forests – Evidences from a qualitative survey in four alpine areas in Austria

Oliver Tamme
Oedl-Wieser, Theresia; Wiesinger, Georg; Grüneis, Heidelinde

Abstract/Description

Natural hazards are a significant cause of threat to life, quality of life and well-being. Moreover, they can have relevant negative impacts on the regional economy, e.g. in regions with tourism industry. The aim of the empirical survey was to analyse the perception of the exposed population of the function of protective forests to prevent or mitigate natural hazards (avalanches, shallow landslides and rockfall). In the context of the project “The importance of protective forests in Austria and their economic relevance”, qualitative interviews with stakeholders, landlords, foresters, representatives from the torrent and avalanche control authority, hunters and NGOs were conducted in four Austrian case study regions (Forst Management Projects (FMP) in Bad Aussee, Kals, Brandberg and Kleines Walsertal). The main areas of interest were (i), risk perception, (ii) problem awareness, (iii) participation and (iv) options for action and solutions. It should be revealed which measures are appropriate to preserve or strengthen the protective forests. One of the most relevant insights is, that it needs people and experts who are able to translate technical and scientific knowledge about natural hazards and the function of protective forests into everyday knowledge and communicate it to the exposed rural population. The building and further development of social capital through co-operation and mutual trust can help exposed communities to cope with natural hazards and severe forest damage events. The ownership structure of protective forests has an impact on the implementation of the FMPs and the condition of the protective forests, e.g. if there is a lack of professionalism in forest management among small forest owners and servitude owners. A “local forester” like in Tyrol and Vorarlberg could be a role model for the sustainable management of protective forests in other regions. A significant limiting factor for safeguarding the protective forests is the conflict area of “forest-wildlife-tourism”. Here, visitor management measures for mountain biking and skiing have proven their worth. Finally, the financial support of protective forest restoration and conservation by the public sector is considered by the interview partners as very important, especially in the light of the climate crisis.

ID: 3.13091

Natural Hazards, Climate Change, and Criminal Liability: Challenges and Legal Frameworks

Margareth Helfer

Abstract/Description

Climate change is significantly transforming the risk profile of natural hazards, particularly in alpine regions where extreme weather-related events, such as avalanches, rockfalls, and floods are increasing in frequency and intensity. These shifting patterns of risk pose critical challenges for risk management and raise fundamental questions regarding legal responsibility. The unpredictability of such disasters renders it challenging to assign responsibility, calling for reorientation of legal frameworks to the evolving risks. The focus is on examining the implications of climatically caused natural hazards for criminal liability. Traditional liability theories are often inadequate to address the complexity of environmental dangers. A central question is to what extent individuals are responsible for their own safety in hazardous environments as opposed to the responsibility of guarantors such as civil protection authorities, avalanche commissions, and geologists. The increasing presence of inexperienced mountaineers further complicates legal assessments, challenging the requirements for more education programs or stricter regulations. One of the most important areas in this study is how scientists and emerging technologies in risk assessment affect risk assessment. Advanced hazard analysis tools and AI-powered prediction models improve decision-making but raise legal questions about liability for system failures or erroneous warnings. It is about to investigate how the use of such technology affects liability attribution and whether existing law address these issues adequately. The broader implications of this study underscore the necessity of reconsider liability norms in the context of climate change. Legal systems must balance responsibility with the understanding that not all risks can be mitigated. Prevention, legal certainty regarding individual versus institutional responsibility, and interdisciplinary dialogue between legal scholars, scientists, and policymakers are essential in the development of a fair and effective legal system for risk management in increasingly vulnerable regions.

ID: 3.13688

Life Cycle Assessment of Century-Old Eco-DRR Strategies in Los Arañones Forest for Protecting Canfranc Railway Station from Natural Hazards

Juan Antonio Ballesteros Canovas
Marsal Twose, Ishel; Muñoz Torrero, Alberto; Sánchez-Silva, Mauricio

Abstract/Description

Natural hazards are recurring processes that often disrupt community stability and pose risks to the future well-being of people. In the Pyrenees, extreme events such as floods, rockfalls, landslides, and snow avalanches have repeatedly affected transport corridors and human settlements. Addressing these challenges in the future requires a transition toward implementing Ecosystem-based Disaster Risk Reduction (Eco-DRR) strategies and sustainable land use practices. However, little is known about the long-term reliability of these approaches. Here, we present a life-cycle analysis of a catchment with over a century of experience in implementing Eco-DRR strategies—Los Arañones—designed to protect the International Railway Station of Canfranc (Spain-France) from snow avalanches and torrential floods. The Eco-DRR implemented in Los Arañones consisted of two different strategies (i) at short term, innovative nature-based design dikes; and (ii) at long term, systematic reforestation of hill slopes. By employing a multi-disciplinary approach that includes climatology, geomorphology, engineering, tree-ring analysis, and modeling, we assess the past, present, and future trajectories of snow avalanches and floods in a catchment where forest engineers have implemented these measures since the early 20th century. Our analysis suggests that these century-old infrastructures still provide effective protection for infrastructure, although maintenance costs to ensure their reliability have increased. Additionally, our findings highlight differences in effectiveness and efficiency due to process changes driven by climate change stressors. We also introduce an initial system designed to monitor the stability of 100-year-old check dams. This case study offers valuable insights for implementing similar solutions in other mountain regions worldwide while providing a foundation for further monitoring and evaluation of such systems.

ID: 3.13788

“Forest Fire Risk and Rural Out-Migration: A Case Study of the Himalayan Ganga Basin (HGB), Central Himalaya”

Rumi Rongpi
Bisht, Hemant Singh

Abstract/Description

Forest fires are increasing in intensity and frequency, posing a significant threat to ecosystems, biodiversity, and human livelihoods. Climate change is widely studied as a primary driver of forest fires; however, factors beyond climate change, such as human activities and land-use changes, have received comparatively less attention. This study aims to bridge this gap by assessing the spatiotemporal trends of forest fires and examining non-climatic factors over the Himalayan Ganga Basin (HGB). Using the Getis-Ord Gi* and Moran’s I spatial statistical methods, forest fire hotspots were analyzed from 2012 to 2024 to identify spatiotemporal patterns. The results reveal a consistent cyclical pattern of forest fire incidents, alternating yearly increases and decreases, except for 2020. The highest fire incidents occurred in 2016 (9,162), followed by a decline in 2017 (1,117). The basin was classified into forest fire risk zones, with 24.8% under very low risk, 42.25% under low risk, 14.10% under moderate risk, 11.91% under high risk, and 6.85% under very high risk. The moderate, high, and very high-risk zones are concentrated in the Pauri Garhwal, Tehri Garhwal, Uttarkashi, and Chamoli districts. This study also investigated the role of rural out-migration. The findings indicate that Pauri Garhwal, Tehri Garhwal, and Uttarkashi are the districts with the highest rates of rural out-migration. As local communities migrate to urban centers in search of better opportunities, traditional land management practices such as controlled burning and forest maintenance are increasingly abandoned. This has led to the accumulation of dry biomass, creating a fuel-rich environment that exacerbates the intensity and frequency of forest fires in the region. The reduction in human intervention has disrupted traditional ecological practices, making forests more vulnerable to uncontrolled fires.

FS 3.150: Methodological advances in mountain research

FS 3.152: Architecture and climate change: explore criticalities and potentials of building in mountain areas within the current environmental crisis

#IMC: September 14 - 18 2025

FS 3.151

Mountain hazards: understanding the key risk drivers beyond climate change

Details

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Keywords

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Submitted Abstracts

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