Title: Snow and Avalanche Science - Highlights of applied avalanche research and forecasting
Examining Snow Avalanche Frequency and Magnitude Active
Snow avalanches pose substantial risks to human safety, commerce, and infrastructure in mountainous regions across the globe. Avalanches also act as drivers of important ecological change by creating and modifying habitat for flora and fauna. To better understand the dynamic processes of avalanches at multiple scales, the USGS Snow and Avalanche project uses a variety of methods to study avalanche magnitude and frequency. By advancing the understanding and predictive capabilities of avalanche disturbance, scientists aim to reduce the hazard to humans and more fully understand the ecological role of avalanches. Results from this project provide land-use planners, natural resource managers, and avalanche forecasters a more thorough understanding of how avalanches act as both a hazard and a driver of landscape change.
What is an avalanche?
An avalanche is a mass of snow sliding, tumbling, or flowing down an inclined surface. Slab avalanches can be particularly powerful and destructive due to the speed and force of the mass of snow and the rush of air that sometimes precedes the avalanche. For a slab avalanches to occur, these four conditions are necessary:
- A sufficiently steep slope (most avalanches occur on slopes between 30 and 45 degrees)
- A weak layer in the snowpack
- A slab of snow above that weak layer
- A trigger initiates the fracture and collapse of the weak layer. Triggers can be the accumulation of snow, rain, wind loading, or human/animal disturbance
How do avalanches impact society?
Hazard - When avalanches intersect with humans, there can be substantial cost associated with impacts to commerce, damage to infrastructure, and loss of human life. In the western United States, avalanches are the most frequently occurring lethal form of mass movement and, on an annual basis, cause more fatalities than earthquakes and all other forms of slope failure combined (Voight et al, 1990). They can also impact roads and railways causing substantial damage and disruption to commerce.
Disturbance - Ecologically, avalanches are instrumental in modifying the landscape and adding ecological complexity to mountain ecosystems. By creating and maintaining paths free of large trees, avalanches disturbance creates a mosaic of vegetation types which support a diverse range of plant and animal species.
Challenge – Avalanches are a complex phenomenon due to the complicated interactions of weather, climate, and snowpack structure, and USGS research assessing current and future trends in avalanche activity aims to fill a knowledge gap needed to improve forecasting and public safety, to protect resources, and to lend insight into the ecological role of avalanches.
Snow and Avalanche Project Research Goals
The ability to improve avalanche forecasting in the context of a changing climate depends on a solid understanding of the interplay between the drivers that contribute to avalanche frequency, magnitude, and character. USGS scientists and their collaborators study avalanches across multiple climatic zones throughout the U.S. Rocky Mountains. Dendrochronology (the study of tree rings) and remote sensing provide scientists opportunities to assess avalanche frequency and behavior in the context of changing climate. Research goals seek to address:
1) how avalanche frequency and character vary across space and time
2) what are the primary climate and atmospheric drivers of avalanche variability
Avalanche science – the past informs the future
To understand the relationships between avalanche cycles and climate, scientists can look back in time using dendrochronology, the study of tree rings, and create a chronology of past avalanche events. Annual growth rings of trees that survive avalanches often hold records of large magnitude avalanche events due to tree damage. This mechanical damage can be visible in many forms including scars, reaction wood, or traumatic resin ducts. USGS scientists collect many tree samples across avalanche path study areas and carefully cross-date the growth rings to build a historic record of large magnitude avalanches for each site.
By coupling these avalanche chronologies with historic climate data, USGS scientists tease apart the topographic and climate factors that contribute to avalanche occurrence at local and regional scales. These techniques assist with the understanding of avalanche cycles in the broader context of atmospheric circulation patterns, such as the Pacific Decadal Oscillation (PDO) or El Niño Southern Oscillation (El Niño and La Niña). Through careful dissection of the connections between past climate and avalanche cycles, USGS scientists aim to provide improved avalanche forecasts to reduce the loss of property and life.
Results from the northern Rocky Mountains
Additional Resources:
- USGS Snow and Avalanche Project overview
- Flathead Avalanche Center - avalanche forecasts for Flathead, Swan & Whitefish Ranges & Glacier National Park
- National Avalanche Center and the American Avalanche Association - avalanche information and backcountry avalanche forecasts for the United States
- Going-to-the-Sun Road Avalanche Forecasting Program - Glacier National Park has implemented an avalanche forecasting program to increase safety during the hazardous plowing season. On-site snowpack and start zone evaluations lead to enhanced avalanche forecasting and real-time snow safety.
- Unraveling the History of Avalanches in Juneau blog
- Going to the Sun Road Avalanche Story Map
Below are data or web applications associated with this project.
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
Below are multimedia items associated with this project.
Title: Snow and Avalanche Science - Highlights of applied avalanche research and forecasting
Below are publications associated with this project.
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
Using structure from motion photogrammetry to examine glide snow avalanches
Case study: 2016 Natural glide and wet slab avalanche cycle, Going-to-the-Sun Road, Glacier National Park, Montana, USA
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.
Avalanche ecology and large magnitude avalanche events: Glacier National Park, Montana, USA
- Overview
Snow avalanches pose substantial risks to human safety, commerce, and infrastructure in mountainous regions across the globe. Avalanches also act as drivers of important ecological change by creating and modifying habitat for flora and fauna. To better understand the dynamic processes of avalanches at multiple scales, the USGS Snow and Avalanche project uses a variety of methods to study avalanche magnitude and frequency. By advancing the understanding and predictive capabilities of avalanche disturbance, scientists aim to reduce the hazard to humans and more fully understand the ecological role of avalanches. Results from this project provide land-use planners, natural resource managers, and avalanche forecasters a more thorough understanding of how avalanches act as both a hazard and a driver of landscape change.
What is an avalanche?
An avalanche is a mass of snow sliding, tumbling, or flowing down an inclined surface. Slab avalanches can be particularly powerful and destructive due to the speed and force of the mass of snow and the rush of air that sometimes precedes the avalanche. For a slab avalanches to occur, these four conditions are necessary:
- A sufficiently steep slope (most avalanches occur on slopes between 30 and 45 degrees)
- A weak layer in the snowpack
- A slab of snow above that weak layer
- A trigger initiates the fracture and collapse of the weak layer. Triggers can be the accumulation of snow, rain, wind loading, or human/animal disturbance
How do avalanches impact society?
Hazard - When avalanches intersect with humans, there can be substantial cost associated with impacts to commerce, damage to infrastructure, and loss of human life. In the western United States, avalanches are the most frequently occurring lethal form of mass movement and, on an annual basis, cause more fatalities than earthquakes and all other forms of slope failure combined (Voight et al, 1990). They can also impact roads and railways causing substantial damage and disruption to commerce.
Disturbance - Ecologically, avalanches are instrumental in modifying the landscape and adding ecological complexity to mountain ecosystems. By creating and maintaining paths free of large trees, avalanches disturbance creates a mosaic of vegetation types which support a diverse range of plant and animal species.
Challenge – Avalanches are a complex phenomenon due to the complicated interactions of weather, climate, and snowpack structure, and USGS research assessing current and future trends in avalanche activity aims to fill a knowledge gap needed to improve forecasting and public safety, to protect resources, and to lend insight into the ecological role of avalanches.
Snow and Avalanche Project Research Goals
The ability to improve avalanche forecasting in the context of a changing climate depends on a solid understanding of the interplay between the drivers that contribute to avalanche frequency, magnitude, and character. USGS scientists and their collaborators study avalanches across multiple climatic zones throughout the U.S. Rocky Mountains. Dendrochronology (the study of tree rings) and remote sensing provide scientists opportunities to assess avalanche frequency and behavior in the context of changing climate. Research goals seek to address:
1) how avalanche frequency and character vary across space and time
2) what are the primary climate and atmospheric drivers of avalanche variability
Avalanche science – the past informs the future
To understand the relationships between avalanche cycles and climate, scientists can look back in time using dendrochronology, the study of tree rings, and create a chronology of past avalanche events. Annual growth rings of trees that survive avalanches often hold records of large magnitude avalanche events due to tree damage. This mechanical damage can be visible in many forms including scars, reaction wood, or traumatic resin ducts. USGS scientists collect many tree samples across avalanche path study areas and carefully cross-date the growth rings to build a historic record of large magnitude avalanches for each site.
By coupling these avalanche chronologies with historic climate data, USGS scientists tease apart the topographic and climate factors that contribute to avalanche occurrence at local and regional scales. These techniques assist with the understanding of avalanche cycles in the broader context of atmospheric circulation patterns, such as the Pacific Decadal Oscillation (PDO) or El Niño Southern Oscillation (El Niño and La Niña). Through careful dissection of the connections between past climate and avalanche cycles, USGS scientists aim to provide improved avalanche forecasts to reduce the loss of property and life.
Results from the northern Rocky Mountains
Additional Resources:
- USGS Snow and Avalanche Project overview
- Flathead Avalanche Center - avalanche forecasts for Flathead, Swan & Whitefish Ranges & Glacier National Park
- National Avalanche Center and the American Avalanche Association - avalanche information and backcountry avalanche forecasts for the United States
- Going-to-the-Sun Road Avalanche Forecasting Program - Glacier National Park has implemented an avalanche forecasting program to increase safety during the hazardous plowing season. On-site snowpack and start zone evaluations lead to enhanced avalanche forecasting and real-time snow safety.
- Unraveling the History of Avalanches in Juneau blog
- Going to the Sun Road Avalanche Story Map
- Data
Below are data or web applications associated with this project.
Avalanche 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. - Multimedia
Below are multimedia items associated with this project.
PubTalk 3/2018 - Snow & Avalanche ScienceTitle: Snow and Avalanche Science - Highlights of applied avalanche research and forecasting
Title: Snow and Avalanche Science - Highlights of applied avalanche research and forecasting
- Publications
Below are publications associated with this project.
Filter Total Items: 13Climate 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 WardUsing 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. FagreCase 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 ClarkExamining 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. FagreAvalanche ecology and large magnitude avalanche events: Glacier National Park, Montana, USA
Large magnitude snow avalanches play an important role ecologically in terms of wildlife habitat, vegetation diversity, and sediment transport within a watershed. Ecological effects from these infrequent avalanches can last for decades. Understanding the frequency of such large magnitude avalanches is also critical to avalanche forecasting for the Going-to-the-Sun Road (GTSR). In January 2009, a lAuthorsDaniel B. Fagre, Erich H. Peitzsch