A regional spatiotemporal analysis of large  magnitude snow avalanches using tree rings

Abstract. Snow avalanches affect transportation corridors and settlements worldwide. In many mountainous regions, robust records of avalanche frequency and magnitude are sparse or non-existent. However, dendrochronological methods can be used to fill this gap and infer historical avalanche patterns. In this study, we developed a tree-ring-based avalanche chronology for large magnitude avalanche events (size ≥∼D3) using dendrochronological techniques for a portion of the US northern Rocky Mountains. We used a strategic sampling design to examine avalanche activity through time and across nested spatial scales (i.e., from individual paths, four distinct subregions, and the region). We analyzed 673 samples in total from 647 suitable trees collected from 12 avalanche paths from which 2134 growth disturbances were identified over the years 1636 to 2017 CE. Using existing indexing approaches, we developed a regional avalanche activity index to discriminate avalanche events from noise in the tree-ring record. Large magnitude avalanches, common across the region, occurred in 30 individual years and exhibited a median return interval of approximately 3 years (mean = 5.21 years). The median large magnitude avalanche return interval (3–8 years) and the total number of avalanche years (12–18) varies throughout the four subregions, suggesting the important influence of local terrain and weather factors. We tested subsampling routines for regional representation, finding that sampling 8 random paths out of a total of 12 avalanche paths in the region captures up to 83 % of the regional chronology, whereas four paths capture only 43 % to 73 %. The greatest value probability of detection for any given path in our dataset is 40 %, suggesting that sampling a single path would capture no more than 40 % of the regional avalanche activity. Results emphasize the importance of sample size, scale, and spatial extent when attempting to derive a regional large magnitude avalanche event chronology from tree-ring records.

Download Full-text

A regional spatio-temporal analysis of large magnitude snow avalanches using tree rings

10.5194/nhess-2020-253 ◽

2020 ◽

Author(s):

Erich Peitzsch ◽

Jordy Hendrikx ◽

Daniel Stahle ◽

Gregory Pederson ◽

Karl Birkeland ◽

...

Keyword(s):

Tree Ring ◽

Activity Index ◽

Spatial Scales ◽

Temporal Analysis ◽

Probability Of Detection ◽

Snow Avalanches ◽

Large Magnitude ◽

Weather Factors ◽

Mountainous Regions ◽

Return Interval

Abstract. Snow avalanches affect transportation corridors and settlements worldwide. In many mountainous regions, robust records of avalanche frequency and magnitude are sparse or non-existent. However, dendrochronological methods can be used to fill this gap and infer historic avalanche patterns. In this study, we developed a tree-ring based avalanche chronology for large magnitude avalanche events using dendrochronological techniques for a sub-region of the northern United States Rocky Mountains. We used a strategic sampling design to examine avalanche activity through time and across nested spatial scales (i.e. from individual paths, four distinct sub-regions, and the region). We analysed 673 total samples from 647 suitable trees collected from 12 avalanche paths, from which 2,134 growth disturbances were identified over years 1636 to 2017 Common Era (C.E.). Using existing indexing approaches, we developed a regional avalanche activity index to discriminate avalanche events from noise in the tree-ring record. Large magnitude avalanches common across the region occurred in 30 individual years and exhibited a median return interval of approximately three years (mean = 5.21 years). The median large magnitude avalanche return interval (3–8 years) and the total number of avalanche years (12–18) vary throughout the four sub-regions, suggesting the important influence of local terrain and weather factors. We tested subsampling routines for regional representation, finding that sampling eight random paths out of a total of 12 avalanche paths in the region captures up to 83 % of the regional chronology, whereas four paths capture only 43 % to 73 %. The greatest value probability of detection for any given path in our dataset is 40 % suggesting that sampling a single path would capture no more than 40 % of the regional avalanche activity. Results emphasize the importance of sample size, scale, and spatial extent when attempting to derive a regional large magnitude avalanche event chronology from tree-ring records.

Download Full-text

Geomorphological analysis of wetland distribution on various spatial scales

Proceedings of the ICA ◽

10.5194/ica-proc-2-112-2019 ◽

2019 ◽

Vol 2 ◽

pp. 1-5

Author(s):

Natsuki Sasaki ◽

Toshihiko Sugai

Keyword(s):

Spatial Scales ◽

Snow Accumulation ◽

Gis Analysis ◽

Aerial Photo Interpretation ◽

Mountainous Regions ◽

Multiple Spatial Scales ◽

Wetland Distribution ◽

Using Data ◽

Geomorphological Analysis ◽

Northern Japan

Abstract. This study introduces some case analyses of wetland distribution on various spatial scales, from nationwide to the area of a wetland group, with a focus on geomorphological feature. Then described the usefulness of GIS analysis in wetland research. The nationwide wetland distribution in Japan showed that wetland density was high at less than 200&thinsp;m and around 1600&ndash;2000&thinsp;m. Wetlands in mountainous regions were concentrated in snowy Quaternary volcanic regions from the center to the northern part of Japan. This implied snow accumulation and topography of volcanic mountains are important for wetland formation. Secondly, we clarified that wetlands were mainly distributed on the gentle slope of original volcanic surfaces and in landslides in the Hachimantai volcanic groups, in the northern Japan, using 10-m grid DEM and aerial photo interpretation. With the higher-resolution data, it was clear that wetlands were arranged depending on the microtopography of landslides and volcanic surfaces and groundwater. Using data with resolution suitable for the target topographical size and combining the results of multiple spatial scales/resolutions, we can understand the origin of wetlands in more detail.

Download Full-text

Mapping landslides from EO data using deep-learning methods

10.5194/egusphere-egu2020-11876 ◽

2020 ◽

Author(s):

Nikhil Prakash ◽

Andrea Manconi ◽

Simon Loew

Keyword(s):

Deep Learning ◽

Learning Strategies ◽

Landslide Hazard ◽

Probability Of Detection ◽

Landslide Inventory ◽

Economic Losses ◽

Learning Methods ◽

High Resolution Data ◽

Horizon 2020 ◽

Mountainous Regions

Landslide hazard has always been a significant source of economic losses and fatalities in the mountainous regions. Knowledge of the spatial extent of the past and present landslide activity, compiled in the form of a landslide inventory map, is essential for effective risk management. High-resolution data acquired by Earth observation (EO) satellites are often used to map landslides by identifying morphological expressions that can be associated with past and/or recent deformation. This is a slow and difficult process as it requires extensive manual efforts. As a result, such maps are not readily available for all the landslide hazard affected regions. Fully automated methods are required to exploit the exponentially increasing amount of EO data available for landslide hazard assessments. In this context, conventional methods like pixel-based and object-based machine learning strategies have been studied extensively in the last decade. Recent advances in convolutional neural network (CNN), a type of deep-learning method, has outperformed other conventional learning methods in similar image interpretation tasks. In this work, we present a deep-learning based method for semantic segmentation of landslides from EO images. We present the results from a study area in the south of Portland in Oregon, USA. The landslide inventory for training and ground truth was extracted from the Statewide Landslide Information Database of Oregon (SLIDO). We were able to achieve a probability of detection (POD) greater than 0.70. This method can also be extended to be used for rapid mapping of landslides after a major triggering event (like earthquake or extreme metrological event) has occurred.This work is done in the framework of European Commission's Horizon 2020 project "BETTER&#8221;. More information is available on the website https://www.ec-better.eu/.

Download Full-text

Assessing the interaction between mountain forests and natural hazards at Nevados de Chillán, Chile, and its implications for Ecosystem-based Disaster Risk Reduction

10.5194/nhess-2017-348 ◽

2017 ◽

Cited By ~ 1

Author(s):

Alejandro Casteller ◽

Thomas Häfelfinger ◽

Erika Cortés Donoso ◽

Karen Podvin ◽

Dominik Kulakowski ◽

...

Keyword(s):

Risk Reduction ◽

Natural Hazards ◽

Tree Ring ◽

Land Use Planning ◽

Disaster Risk Reduction ◽

Disaster Risk ◽

Process Models ◽

Snow Avalanches ◽

Tree Ring Data ◽

Risk Reduction Measure

Abstract. Gravitational natural hazards such as snow avalanches, rockfalls, shallow landslides and volcanic activity represent a risk factor for mountain communities around the world. In particular where documentary records about these processes are rare, decisions on risk management and land-use planning have to be based on a variety of other sources including vegetation and tree-ring data and natural hazard process models. We used a combination of these methods in order to evaluate dynamics of snow avalanches and other natural hazards at Valle de las Trancas, in the Biobío Region in Chile. Along this valley, natural hazards threaten not only the local human population, but also the numerous tourists attracted by outdoor recreational activities. Given the regional scarcity of documentary records, tree-ring methods were applied in order to reconstruct the local history of snow avalanches and debris flow events, which are the more important weather-related processes at respective tracks. A recent version of the model Rapid Mass MovementS (RAMMS), that includes influences of forest structure, was used to calculate different avalanche parameters such as runout distances and maximum pressures, taking into consideration the presence/absence of forest along the tracks as well as different modelled return periods. Our results show that local Nothofagus broadleaved forests contribute to a reduction of avalanche runout distances as well as impact pressures on present infrastructure, thus constituting a valuable ecosystem disaster risk reduction measure that can substitute or complement other traditional measures such as sheds.

Download Full-text

Evaluation of Whole Tree Growth Increment Derived from Tree-Ring Series for Use in Assessments of Changes in Forest Productivity across Various Spatial Scales

Forests ◽

10.3390/f7120303 ◽

2016 ◽

Vol 7 (12) ◽

pp. 303 ◽

Cited By ~ 7

Author(s):

Juha Metsaranta ◽

Jagtar Bhatti

Keyword(s):

Tree Ring ◽

Tree Growth ◽

Spatial Scales ◽

Forest Productivity ◽

Growth Increment ◽

Whole Tree

Download Full-text

A Reconstruction of Snow-Avalanche Characteristics in Montana, U.S.A., Using Vegetative Indicators

Journal of Glaciology ◽

10.1017/s0022143000006444 ◽

1985 ◽

Vol 31 (108) ◽

pp. 185-187 ◽

Cited By ~ 38

Author(s):

David R. Butler ◽

George P. Malanson

Keyword(s):

Tree Ring ◽

National Park ◽

Natural Hazard ◽

Snow Avalanche ◽

Glacier National Park ◽

Snow Avalanches ◽

Southern Boundary ◽

Tree Ring Data ◽

Wet Snow

AbstractWidespread wet-snow avalanches were observed on the southern boundary of Glacier National Park, Montana, in February 1979. Severe tilting, scarring, and breakage of trees were observed along a transverse trim-line of one path, 70 m from a wet-snow deposit. Tree-ring data were used to establish the date of occurrence, and the nature of damage was used to characterize the avalanche event. The event probably included a previously unrecognized dry-snow avalanche and associated wind blast. Such events present different problems for natural-hazard planning. The nature of vegetative damage along the margins of avalanche paths is shown to be a useful indicator of the characteristics of past unobserved avalanche events.

Download Full-text

Assessing the interaction between mountain forests and snow avalanches at Nevados de Chillán, Chile and its implications for ecosystem-based disaster risk reduction

Natural Hazards and Earth System Science ◽

10.5194/nhess-18-1173-2018 ◽

2018 ◽

Vol 18 (4) ◽

pp. 1173-1186 ◽

Cited By ~ 9

Author(s):

Alejandro Casteller ◽

Thomas Häfelfinger ◽

Erika Cortés Donoso ◽

Karen Podvin ◽

Dominik Kulakowski ◽

...

Keyword(s):

Risk Reduction ◽

Natural Hazards ◽

Tree Ring ◽

Land Use Planning ◽

Disaster Risk Reduction ◽

Disaster Risk ◽

Process Models ◽

Snow Avalanches ◽

Tree Ring Data ◽

Risk Reduction Measure

Abstract. Gravitational natural hazards such as snow avalanches, rockfalls, shallow landslides and volcanic activity represent a risk to mountain communities around the world. In particular, where documentary records about these processes are rare, decisions on risk management and land-use planning have to be based on a variety of other sources including vegetation, tree-ring data and natural hazard process models. We used a combination of these methods in order to evaluate dynamics of natural hazards with a focus on snow avalanches at Valle Las Trancas, in the Biobío region in Chile. Along this valley, natural hazards threaten not only the local human population, but also the numerous tourists attracted by outdoor recreational activities. Given the regional scarcity of documentary records, tree-ring methods were applied in order to reconstruct the local history of snow avalanches and debris flow events, which are the most important weather-related processes at respective tracks. A recent version of the model Rapid Mass MovementS (RAMMS), which includes influences of forest structure, was used to calculate different avalanche parameters such as runout distances and maximum pressures, taking into consideration the presence or absence of forest along the tracks as well as different modeled return periods. Our results show that local Nothofagus broadleaf forests contribute to a reduction of avalanche runout distances as well as impact pressure on present infrastructure, thus constituting a valuable ecosystem disaster risk reduction measure that can substitute or complement other traditional measures such as snow sheds.

Download Full-text

Validation of extreme snow avalanches and related return periods derived from a statistical-dynamical model using tree-ring techniques

Cold Regions Science and Technology ◽

10.1016/j.coldregions.2013.12.001 ◽

2014 ◽

Vol 99 ◽

pp. 12-26 ◽

Cited By ~ 30

Author(s):

Romain Schläppy ◽

Nicolas Eckert ◽

Vincent Jomelli ◽

Markus Stoffel ◽

Delphine Grancher ◽

...

Keyword(s):

Tree Ring ◽

Dynamical Model ◽

Return Periods ◽

Snow Avalanches

Download Full-text

Dendroclimatology in the Eastern Mediterranean

Radiocarbon ◽

10.1017/s0033822200050360 ◽

2014 ◽

Vol 56 (04) ◽

pp. S61-S68

Author(s):

Ramzi Touchan ◽

David M. Meko ◽

Kevin J. Anchukaitis

Keyword(s):

Resource Management ◽

Climate Variability ◽

20Th Century ◽

Tree Ring ◽

Large Scale ◽

Eastern Mediterranean ◽

Spatial Scales ◽

Climatic Variation ◽

Ring Network ◽

The Past

Dendroclimatology in the Eastern Mediterranean (EM) region has made important contributions to the understanding of climate variability on timescales of decades to centuries. These contributions, beginning in the mid-20th century, have value for resource management, archaeology, and climatology. A gradually expanding tree-ring network developed by the first author over the past 15 years has been the framework for some of the most important recent advances in EM dendroclimatology. The network, now consisting of 79 sites, has been widely applied in large-scale climatic reconstruction and in helping to identify drivers of climatic variation on regional to global spatial scales. This article reviews EM dendroclimatology and highlights contributions on the national and international scale.

Download Full-text

Reconstructing snow-avalanche activity with tree rings in Maramureş Mountains (Eastern Carpathians, Romania)

10.5194/egusphere-egu2020-20060 ◽

2020 ◽

Author(s):

Armelle Decaulne ◽

Ionela-Georgiana Răchită ◽

Mihai Hotea ◽

Vasile Timur Chiş ◽

Olimpiu Traian Pop

Keyword(s):

Tree Ring ◽

Tree Rings ◽

Climatic Factors ◽

Climatic Conditions ◽

Snow Avalanche ◽

Snow Avalanches ◽

Joint Research ◽

Eastern Carpathians ◽

Joint Research Project ◽

Callus Tissues

Snow avalanches represent a common phenomenon in Maramure&#351; Mountains (Eastern Carpathians, Romania) where they occur frequently on higher steep slopes and reach in the runout zones the valley bottoms below 1000 m a.s.l. The presence of particular topo-climatic conditions influences the patterns of avalanche activity in terms of past frequency and spatial extent along the slope valleys. As the past snow-avalanche activity is not documented by written reports in the area, reliable information about avalanche history is missing. However, the slopes are forested, trees repeatedly disturbed by snow avalanches record evidence of past events. For this study we reconstructed the avalanche activity using tree rings as a source of proxy data. To date the snow-avalanche history, dendrochronological investigations have been carried out in two avalanche paths, along which living trees showed clear external signs of past disturbances related to mechanical impacts produced by snow avalanches. In each investigated path, a total number of 52 and respectively 118 trees have been sampled and their spatial position recorded with a GPS device. Tree-growth anomalies (e.g. scars, callus tissues, the onset sequences of tangential rows of traumatic resin ducts, compression wood, growth suppression and release sequences) related to snow avalanche disturbance identified within tree rings served to reconstruct past events with an annual resolution. The results indicate that, apart the 2005 major event witnessed and also confirmed by tree-ring dating, multiple other events have been reconstructed since the beginning of 20th century. Despite some inherent limitations of tree-ring methods in reconstructing past avalanche events, these dendrochronological investigations confirm their utility in deciphering the patterns of avalanche activity in Maramure&#351; Mountains. Tree-ring studies contribute to a better understanding of the role of topographical and climatic factors which influence the spatio-temporal occurrence of snow avalanches.This study represents a contribution to the joint research project 09-AUF, &#8216;&#8216;Activit&#233; des avalanches de neige dans les Carpates Orientales Roumaines et Ukrainiennes - ACTIVNEIGE&#8217;&#8217;, co-funded by the Agence Universitaire de la Francophonie (AUF) and Institutul de Fizic&#259; Atomic&#259; (IFA), Romania.

Download Full-text