Snow avalanches are a widespread natural hazard to humans and infrastructure as well as an important landscape disturbance affecting mountain ecosystems. Forecasting avalanche frequency is challenging on various spatial and temporal scales, and this project aims to fill a gap in snow science by focusing on reconstructing avalanche history on the continental mountain range scale - throughout the Rocky Mountains and into southeast Alaska. This should provide an opportunity to more thoroughly assess current and future trends in avalanche activity and, ultimately, improve public safety and protect resources. The project aims to advance our understanding of avalanche frequency, magnitude, and character changes and to improve estimates of future changes in these types of avalanche parameters in the context of changing climate drivers. In other words, how does avalanche frequency and character vary across space and time, and what are the primary drivers of this variability?
Statement of Problem: In the western United States, avalanches are the most frequently occurring lethal form of slope movement and, on an annual basis, cause more fatalities than earthquakes and all other forms of slope failure combined. Avalanches affect a substantial portion of society, including human safety and commerce, and also serve as a major driver of ecological disturbance by modifying habitat for flora and fauna. Economic impacts due to avalanches in the western United States are substantial. For instance, the economic loss when Interstate-70 through Colorado closes due to avalanche impacts is approximately $1 million per hour ($3330/ lane mile hour). In addition, avalanches impact the spring opening operations of the Going-to-the-Sun Road, a major attraction in Glacier National Park, where visitors contribute $344 million to surrounding communities.
- Determine avalanche frequency across multiple spatial scales by incorporating tree ring records, historical observations, and remote sensing (UAS) tools.
- Determine the weather, climate, and snowpack drivers of large magnitude avalanche events and assess variability across multiple spatio-temporal scales and avalanche climates.
- Examine climate and weather drivers to assess a historical and ongoing shift in avalanche character across different spatial extents and avalanche climates.
Methods:
Reconstructing past avalanche frequency using tree-rings - Trees are susceptible to damage from geomorphic processes such as avalanches, and individual trees record the effects of the disturbance in several ways. An avalanche may cause wounds on the tree trunk or branches. It can also locally destroy the cambium (plant cells responsible for plant diameter increasing), causing disruption of new cell formation. As a result, the tree then produces tissue and the cells overgrow the injury forming a “scar” on the tree-ring. Other markers of mechanical disturbance from avalanches in tree ring records include reaction wood (created in response to gravity to push a tree back to a vertical position) and traumatic resin ducts (created after injury to deliver more resin, an antiseptic, to injured part of tree).
We collect cross-sectional wood samples from dead (both downed and standing dead) trees and trunk core samples from live trees. We process, date, and measure tree ring widths using standard procedures, and then process the samples for signs of traumatic impact events likely caused by snow avalanches. Using the resulting avalanche event chronologies, the return periods for each path, sub-region, and entire study site are estimated. Chronologies from the northern Rockies (intermountain avalanche climate) and southeast Alaska (maritime avalanche climate) were previously collected and will be used in this study to examine potential geographic differences in avalanche frequency within the Rocky Mountain cordillera and variability within and between avalanche climates. Finally, we use historical avalanche occurrence records from throughout the study area to assess the tree-ring derived chronology in more recent times.
Atmospheric and climate drivers of large magnitude avalanches - Understanding the spatio-temporal behavior of avalanches and the contributing climate factors is important for understanding climate variability, interpreting historical avalanche variability, and improving avalanche forecasting. We use the reconstructed avalanche chronologies and existing historical datasets as well as climate databases to examine relationships between years of large magnitude avalanche events and climate variables. We will begin by investigating trends in wet snow avalanche frequency throughout the study site using historical observational datasets.
Using remote sensing to examine avalanche and snowpack characteristics - Snow depth varies both among sites and within a season. The amount of weater stored as snow has direct impacts on water availability and flooding that could affect downstream communities. The seasonal evolution of the spatial distribution of snow depth reflects water storage information that is valuable to resource managers and downstream communities concerned about water availability and flooding. Snow distribution data on shorter time scales are necessary for avalanche risk assessment. New methods have been developed to estimate snowpack variability and the amount of water stored in snowpack, using Unmanned Aerial Systems (UASs) and Structure-from-Motion (SfM) photogrammetry. Aerial images of complex alpine terrain were collected in the winter using UAS and high-resolution GPS measurements. These images are then processed using photogrammetry software and programming language platforms to build geo-referenced digital elevation products. A variety of statistical techniques are then employed to assess variability of snow depth change and avalanche frequency across the sites and through time.
We also are exploring use of satellite imagery to detect landscape change due to avalanche disturbance. We are also working on pattern recognition techniques to identify changes in properties of multi-band spectral imagery after the March 2019 historic avalanche cycle in Colorado. In addition, preliminary exploratory analysis shows strong potential for use of historical imagery time series to examine changes in vegetation within and around avalanche paths to provide another measure of avalanche frequency.
The Western Mountain Initiative (WMI)
Accelerating changes and transformations in western mountain lakes
Effects of disturbance and drought on the forests and hydrology of the Southern Rocky Mountains
Forest health and drought response
Below are data or web applications associated with this project.
2020 winter timeseries of UAS derived digital surface models (DSMs) from the Hourglass study site, Bridger Mountains, Montana, USA
Avalanche occurrence records along the Going-to-the-Sun Road, Glacier National Park, Montana from 2003-2023 (ver. 3.0, July 2023)
Tree ring dataset for a regional avalanche chronology in northwest Montana, 1636-2017
Climate drivers of large magnitude snow avalanche years in the U.S. northern Rocky Mountains
A regional spatio-temporal analysis of large magnitude snow avalanches using tree rings
Research Note: How old are the people who die in avalanches? A look into the ages of avalanche victims in the United States (1950-2018)
Detecting snow depth change in avalanche path starting zones using uninhabited aerial systems and structure from motion photogrammetry
Identifying major avalanche years from a regional tree-ring based avalanche chronology for the U.S. Northern Rocky Mountains
On the exchange of sensible and latent heat between the atmosphere and melting snow
Case study: 2016 Natural glide and wet slab avalanche cycle, Going-to-the-Sun Road, Glacier National Park, Montana, USA
Using structure from motion photogrammetry to examine glide snow avalanches
Terrain parameters of glide snow avalanches and a simple spatial glide snow avalanche model
Examining spring wet slab and glide avalanche occurrence along the Going-to-the-Sun Road corridor, Glacier National Park, Montana, USA
Time lapse photography as an approach to understanding glide avalanche activity
Timing of wet snow avalanche activity: An analysis from Glacier National Park, Montana, USA.
Below are partners associated with this project.
- Overview
Snow avalanches are a widespread natural hazard to humans and infrastructure as well as an important landscape disturbance affecting mountain ecosystems. Forecasting avalanche frequency is challenging on various spatial and temporal scales, and this project aims to fill a gap in snow science by focusing on reconstructing avalanche history on the continental mountain range scale - throughout the Rocky Mountains and into southeast Alaska. This should provide an opportunity to more thoroughly assess current and future trends in avalanche activity and, ultimately, improve public safety and protect resources. The project aims to advance our understanding of avalanche frequency, magnitude, and character changes and to improve estimates of future changes in these types of avalanche parameters in the context of changing climate drivers. In other words, how does avalanche frequency and character vary across space and time, and what are the primary drivers of this variability?
An avalanche that occurred above the Going-to-the-Sun Road, Glacier National Park, MT. May 5, 2011. Statement of Problem: In the western United States, avalanches are the most frequently occurring lethal form of slope movement and, on an annual basis, cause more fatalities than earthquakes and all other forms of slope failure combined. Avalanches affect a substantial portion of society, including human safety and commerce, and also serve as a major driver of ecological disturbance by modifying habitat for flora and fauna. Economic impacts due to avalanches in the western United States are substantial. For instance, the economic loss when Interstate-70 through Colorado closes due to avalanche impacts is approximately $1 million per hour ($3330/ lane mile hour). In addition, avalanches impact the spring opening operations of the Going-to-the-Sun Road, a major attraction in Glacier National Park, where visitors contribute $344 million to surrounding communities.
Why this Research is Important: This project addresses two major impacts of avalanches at the societal level: avalanches as a hazard and avalanches as a disturbance. Results from the work will fill a critical gap in understanding the relationship between avalanches and climate. This research will increase our understanding of this relationship across a large spatial extent and will ultimately improve public safety, aid in mitigating avalanche impacts on commerce through avalanche-prone regions and provide a more thorough understanding of avalanches as a landscape-level disturbance.Avalanche debris from a previous avalanche in the Red Rocks avalanche path along the Going-to-the-Sun Road, Glacier National Park, MT. April 2010. Objective(s):- Determine avalanche frequency across multiple spatial scales by incorporating tree ring records, historical observations, and remote sensing (UAS) tools.
- Determine the weather, climate, and snowpack drivers of large magnitude avalanche events and assess variability across multiple spatio-temporal scales and avalanche climates.
- Examine climate and weather drivers to assess a historical and ongoing shift in avalanche character across different spatial extents and avalanche climates.
Methods:
A tree cross section from a dead tree in Glacier National Park, MT illustrating mechanical injuries to tree rings caused by avalanches. Reconstructing past avalanche frequency using tree-rings - Trees are susceptible to damage from geomorphic processes such as avalanches, and individual trees record the effects of the disturbance in several ways. An avalanche may cause wounds on the tree trunk or branches. It can also locally destroy the cambium (plant cells responsible for plant diameter increasing), causing disruption of new cell formation. As a result, the tree then produces tissue and the cells overgrow the injury forming a “scar” on the tree-ring. Other markers of mechanical disturbance from avalanches in tree ring records include reaction wood (created in response to gravity to push a tree back to a vertical position) and traumatic resin ducts (created after injury to deliver more resin, an antiseptic, to injured part of tree).
We collect cross-sectional wood samples from dead (both downed and standing dead) trees and trunk core samples from live trees. We process, date, and measure tree ring widths using standard procedures, and then process the samples for signs of traumatic impact events likely caused by snow avalanches. Using the resulting avalanche event chronologies, the return periods for each path, sub-region, and entire study site are estimated. Chronologies from the northern Rockies (intermountain avalanche climate) and southeast Alaska (maritime avalanche climate) were previously collected and will be used in this study to examine potential geographic differences in avalanche frequency within the Rocky Mountain cordillera and variability within and between avalanche climates. Finally, we use historical avalanche occurrence records from throughout the study area to assess the tree-ring derived chronology in more recent times.
Atmospheric and climate drivers of large magnitude avalanches - Understanding the spatio-temporal behavior of avalanches and the contributing climate factors is important for understanding climate variability, interpreting historical avalanche variability, and improving avalanche forecasting. We use the reconstructed avalanche chronologies and existing historical datasets as well as climate databases to examine relationships between years of large magnitude avalanche events and climate variables. We will begin by investigating trends in wet snow avalanche frequency throughout the study site using historical observational datasets.
A National Park Service bulldozer cuts through avalanche debris from a large magnitude avalanche along the Going-to-the-Sun Road, Glacier National Park, MT. April 2009. Using remote sensing to examine avalanche and snowpack characteristics - Snow depth varies both among sites and within a season. The amount of weater stored as snow has direct impacts on water availability and flooding that could affect downstream communities. The seasonal evolution of the spatial distribution of snow depth reflects water storage information that is valuable to resource managers and downstream communities concerned about water availability and flooding. Snow distribution data on shorter time scales are necessary for avalanche risk assessment. New methods have been developed to estimate snowpack variability and the amount of water stored in snowpack, using Unmanned Aerial Systems (UASs) and Structure-from-Motion (SfM) photogrammetry. Aerial images of complex alpine terrain were collected in the winter using UAS and high-resolution GPS measurements. These images are then processed using photogrammetry software and programming language platforms to build geo-referenced digital elevation products. A variety of statistical techniques are then employed to assess variability of snow depth change and avalanche frequency across the sites and through time.
We also are exploring use of satellite imagery to detect landscape change due to avalanche disturbance. We are also working on pattern recognition techniques to identify changes in properties of multi-band spectral imagery after the March 2019 historic avalanche cycle in Colorado. In addition, preliminary exploratory analysis shows strong potential for use of historical imagery time series to examine changes in vegetation within and around avalanche paths to provide another measure of avalanche frequency.
An avalanche forecaster approaches the debris and crown of an avalanche that previously occurred above the Going-to-the-Sun Road, Glacier National Park, MT. May 6, 2011. - Science
The Western Mountain Initiative (WMI)
Western Mountain Initiative (WMI) is a long-term collaboration between FORT, WERC, NOROCK, USFS, NPS, LANL, and universities worldwide to address changes in montane forests and watersheds due to climate change. Current emphases include altered forest disturbance regimes (fire, die-off, insect outbreaks) and hydrology; interactions between plants, water, snow, nutrient cycles, and climate; and...Accelerating changes and transformations in western mountain lakes
While research into eutrophication has been a cornerstone of limnology for more than 100 years, only recently has it become a topic for the remote alpine lakes that are icons of protected national parks and wilderness areas. National park lakes in the western U.S. are threatened by global change, specifically air pollution, warming, and their interactions, and the problem is quickly worsening...Effects of disturbance and drought on the forests and hydrology of the Southern Rocky Mountains
Climate-related forest disturbances, particularly drought-induced tree mortality and large, high-severity fires from increasingly warm and dry conditions, are altering forest ecosystems and the ecosystem services society depends on (e.g., water supplies). Our research combines long-term place-based ecological data, diverse methods (e.g., paleo, remote-sensing), and networking approaches to...Forest health and drought response
Forests provide society with economically important and often irreplaceable goods and services, such as wood products, carbon sequestration, clean water, biodiversity, and recreational opportunities. Yet hotter droughts (droughts in which unusually high temperatures exacerbate the effects of low precipitation) are projected to increase in frequency and intensity in coming decades, potentially... - Data
Below are data or web applications associated with this project.
2020 winter timeseries of UAS derived digital surface models (DSMs) from the Hourglass study site, Bridger Mountains, Montana, USA
Unmanned Aerial System (UAS) flights were conducted over the headwaters of the South Fork of Brackett Creek in the Bridger Mountains of SW Montana during the winter of 2020. The flights collected overlapping imagery focused on a steep mountain couloir study site known locally as "the Hourglass." Structure from motion (SfM) photogrammetry was used to process the collected imagery and create digitalAvalanche occurrence records along the Going-to-the-Sun Road, Glacier National Park, Montana from 2003-2023 (ver. 3.0, July 2023)
Starting in 2003, the U.S. Geological Survey (USGS) Northern Rocky Mountain Science Center in West Glacier, MT, in collaboration with the National Park Service, collected avalanche observations along the Going to the Sun Road during the spring road-clearing operations. The spring road-clearing along Going to the Sun Road utilized a team of avalanche specialists from the USGS and Glacier National PTree ring dataset for a regional avalanche chronology in northwest Montana, 1636-2017
This dataset includes processed tree ring data from avalanche paths in Glacier National Park and the Flathead National Forest in northwest Montana. The data were processed in three distinct phases that resulted in this dataset: collection, processing, and avalanche signal analysis. This dataset consists of samples from 647 trees with 2304 growth disturbances identified from 12 avalanche paths. - Publications
Filter Total Items: 14
Climate drivers of large magnitude snow avalanche years in the U.S. northern Rocky Mountains
Large magnitude snow avalanches pose a hazard to humans and infrastructure worldwide. Analyzing the spatiotemporal behavior of avalanches and the contributory climate factors is important for understanding historical variability in climate-avalanche relationships as well as improving avalanche forecasting. We used established dendrochronological methods to develop a long-term (1867–2019) regionalAuthorsErich Peitzsch, Gregory T. Pederson, Karl W. Birkeland, Jordy Hendrikx, Daniel B. FagreA regional spatio-temporal analysis of large magnitude snow avalanches using tree rings
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 (sizeAuthorsErich Peitzsch, Jordy Hendrikx, Daniel Kent Stahle, Gregory T. Pederson, Karl W. Birkeland, Daniel B. FagreResearch Note: How old are the people who die in avalanches? A look into the ages of avalanche victims in the United States (1950-2018)
Since the winter of 1950-1951, 1084 individuals perished in snow avalanches in the United States. In this study, we analyze the ages of those killed (n=900) by applying non-parametric methods to annual median ages and for age groups and primary activity groups. Change point detection results suggest a significant change in 1990 in the median age of avalanche fatalities. Significant positive trendsAuthorsErich Peitzsch, Sara Boilen, Karl W. Birkeland, Spencer LoganDetecting snow depth change in avalanche path starting zones using uninhabited aerial systems and structure from motion photogrammetry
Understanding snow depth distribution and change is useful for avalanche forecasting and mitigation, runoff forecasting, and infrastructure planning. Advances in remote sensing are improving the ability to collect snow depth measurements. The development of structure from motion (SfM), a photogrammetry technique, combined with the use of uninhabited aerial systems (UASs) allows for high resolutionAuthorsErich H. Peitzsch, Daniel B. Fagre, Jordy Hendrikx, Karl W. BirkelandIdentifying major avalanche years from a regional tree-ring based avalanche chronology for the U.S. Northern Rocky Mountains
Avalanches not only pose a major hazard to people and infrastructure, but also act as an important ecological disturbance. In many mountainous regions in North America, including areas with existing transportation corridors, reliable and consistent avalanche records are sparse or non-existent. Thus, inferring long-term avalanche patterns and associated contributory climate and weather factors reAuthorsErich H. Peitzsch, Daniel B. Fagre, Gregory T. Pederson, Jordy Hendrikx, Karl W. Birkeland, Daniel StahleOn the exchange of sensible and latent heat between the atmosphere and melting snow
The snow energy balance is difficult to measure during the snowmelt period, yet critical for predictions of water yield in regions characterized by snow cover. Robust simplifications of the snowmelt energy balance can aid our understanding of water resources in a changing climate. Research to date has demonstrated that the net turbulent flux (FT) between a melting snowpack and the atmosphere is neAuthorsPaul C. Stoy, Erich H. Peitzsch, David J. A. Wood, Daniel Rottinghaus, Georg Wohlfahrt, Michael Goulden, Helen WardCase study: 2016 Natural glide and wet slab avalanche cycle, Going-to-the-Sun Road, Glacier National Park, Montana, USA
The Going-to-the-Sun Road (GTSR) is the premier tourist attraction in Glacier National Park, Montana. The GTSR also traverses through and under 40 avalanche paths which pose a hazard to National Park Service (NPS) road crews during the annual spring snow plowing operation. Through a joint collaboration between the NPS and the U.S. Geological Survey (USGS), a forecasting program primarily dealing wAuthorsJacob Hutchinson, Erich H. Peitzsch, Adam ClarkUsing structure from motion photogrammetry to examine glide snow avalanches
Structure from Motion (SfM), a photogrammetric technique, has been used extensively and successfully in many fields including geosciences over the past few years to create 3D models and high resolution digital elevation models (DEMs) from aerial or oblique photographs. SfM has recently been used in a limited capacity in snow avalanche research and shows promise as a tool for broader applications.AuthorsErich H. Peitzsch, Jordy Hendrikx, Daniel B. FagreTerrain parameters of glide snow avalanches and a simple spatial glide snow avalanche model
Glide snow avalanches are dangerous and difficult to predict. Despite substantial recent research there is still inadequate understanding regarding the controls of glide snow avalanche release. Glide snow avalanches often occur in similar terrain or the same locations annually, and repeat observations and prior work suggest that specific topography may be critical. Thus, to gain a better understanAuthorsErich H. Peitzsch, Jordy Hendrikx, Daniel B. FagreExamining spring wet slab and glide avalanche occurrence along the Going-to-the-Sun Road corridor, Glacier National Park, Montana, USA
Wet slab and glide snow avalanches are dangerous and yet can be particularly difficult to predict. Wet slab and glide avalanches are presumably triggered by free water moving through the snowpack and the subsequent interaction with layer or ground interfaces, and typically occur in the spring during warming and subsequent melt periods. In Glacier National Park (GNP), Montana, both types of avalancAuthorsErich H. Peitzsch, Jordy Hendrikx, Daniel B. Fagre, Blase ReardonTime lapse photography as an approach to understanding glide avalanche activity
Avalanches resulting from glide cracks are notoriously difficult to forecast, but are a recurring problem for numerous avalanche forecasting programs. In some cases glide cracks are observed to open and then melt away in situ. In other cases, they open and then fail catastrophically as large, full-depth avalanches. Our understanding and management of these phenomena are currently limited. It is thAuthorsJordy Hendrikx, Erich H. Peitzsch, Daniel B. FagreTiming of wet snow avalanche activity: An analysis from Glacier National Park, Montana, USA.
Wet snow avalanches pose a problem for annual spring road opening operations along the Going-to-the-Sun Road (GTSR) in Glacier National Park, Montana, USA. A suite of meteorological metrics and snow observations has been used to forecast for wet slab and glide avalanche activity. However, the timing of spring wet slab and glide avalanches is a difficult process to forecast and requires new capabilAuthorsErich H. Peitzsch, Jordy Hendrikx, Daniel B. Fagre - Partners
Below are partners associated with this project.