Publications
Below is a list of available NOROCK peer reviewed and published science. If you are in search of a specific publication and cannot find it below or through a search, please contact twojtowicz@usgs.gov.
Filter Total Items: 1357
Applying automated avalanche terrain mapping to wildlife ecology: A case study of Dall's sheep in southcentral Alaska Applying automated avalanche terrain mapping to wildlife ecology: A case study of Dall's sheep in southcentral Alaska
Avalanche hazard has been studied extensively in the context of human risk, but its role in alpine wildlife ecology remains poorly understood. Long-term telemetry studies have revealed that avalanches are an important source of mortality for some mountain ungulates. Investigating the processes underlying these events is challenging because avalanche activity and snowpack conditions are...
Authors
Heather Thamm, John Sykes, Nicholas Fowler, Thomas Lohuis, Kyle Smith, Erich Peitzsch, Todd Brinkman, Ophelie Couriot
Tracking water in snow: Bridging sensor and and model simulations Tracking water in snow: Bridging sensor and and model simulations
Forecasting wet slab avalanches remains one of the most demanding challenges in operational avalanche forecasting. A key obstacle is the difficulty of observing and quantifying liquid water content (LWC) and tracking its infiltration into the snowpack. Field measurements are labor-intensive, highly variable in space, and often influenced by user application or sensor design — making them
Authors
Andrea Bruckmeier, Christoph Mitterer, Robyn Gotz, Eric Sproles, Erich Peitzsch
Climate-driven shifts in snowpack conditions favorable for wet snow avalanches: Insights from snow cover model simulations Climate-driven shifts in snowpack conditions favorable for wet snow avalanches: Insights from snow cover model simulations
Forecasting wet snow avalanches remains a major challenge due to their temporal and spatial variability. Long-term climate trends are producing more variable and extreme weather, creating conditions outside historical experience, and increasing forecasting uncertainties. To assess how climate change affects the frequency and timing of wet snow avalanches, we examined the long-term...
Authors
Andrea Bruckemeier, Christoph Mitterer, Karl W. Birkeland, Eric Sproles, Erich Peitzsch
Start-zone characteristics and timing of wet slab avalanches In Colorado Start-zone characteristics and timing of wet slab avalanches In Colorado
Wet slab avalanches (WSAs) release when liquid water reduces the strength of a buried weak layer or interface, and their timing is governed primarily by the snowpack energy balance and the movement of meltwater. We classified 717 WSAs from the Colorado Avalanche Information Center database (2011–2025) into five start-zone terrain categories and analysed the timing of naturally triggered...
Authors
Brandon Levy, Ron Simenhois, Erich Peitzsch, Ethan M. Greene
Revisiting avalanche destructive scale and associated mass estimates Revisiting avalanche destructive scale and associated mass estimates
Avalanche destructive (D) size classifications are essential for forecasting, communication, and risk management, yet size estimation remains one of the more subjective elements of avalanche assessment. Practitioners typically rely on visual impressions of destructive potential, path length, and estimated mass and volume. Recent work indicates that size is often underestimated even by...
Authors
Erich Peitzsch, John Sykes, Zachary Guy, Ron Simenhois, Bruce Jamieson
Patterns of glide avalanche release: Insights from 23 years of observations along the Going-to-the-Sun Road, Montana, USA Patterns of glide avalanche release: Insights from 23 years of observations along the Going-to-the-Sun Road, Montana, USA
Glide avalanches pose a notable hazard during annual spring snow removal operations along the Going-to-the-Sun Road (GTSR) in Glacier National Park (GNP), USA. Glide cracks consistently form on specific slopes near and above the GTSR. Some glide crack locations produce glide avalanches most years (known as repeater paths), whereas others are less predictable and either release or melt in...
Authors
Erika Hart Birkeland, Maddey Jude Frey, Sarah Elizabeth Williams, Erich Peitzsch
Stability changes after weak layer collapse: Insights from an unexpected dataset Stability changes after weak layer collapse: Insights from an unexpected dataset
While conducting avalanche mitigation or traveling through the backcountry, avalanche professionals sometimes experience a "whumpf": a collapse-mode crack accompanied by surface cracking that does not produce an avalanche. These whumpfs are a clear warning sign of instability in the surrounding terrain. But assessing the collapsed slope itself, if it is steep enough to avalanche, carries...
Authors
Andrea Bruckmeier, Erika Hart Birkeland, Ron Simenhois, Alex Marienthal, Erich Peitzsch, Karl W. Birkeland
Establishing conservation benchmarks for threatened Bull Trout using spawner-recruitment relationships Establishing conservation benchmarks for threatened Bull Trout using spawner-recruitment relationships
Understanding the relationship between breeding adults and juvenile recruitment is fundamental to conserving at-risk species. Knowing whether recruitment is depensatory or compensatory at low adult abundances can aid in developing conservation strategies and recovery goals. However, this relationship requires long-term monitoring of two life stages, which can be costly and uncommon...
Authors
Hayley Corrine Glassic, Robert Al-Chokhachy, Leo R. Rosenthal, Matthew C. Boyer, Thomas Weaver, Kristen L. Cook, David Schmetterling, Ryan P. Kovach, Clint C. Muhlfeld, Timothy Cline
Temporal replication and sampling efficiency in high-frequency autonomous and manual eDNA sampling Temporal replication and sampling efficiency in high-frequency autonomous and manual eDNA sampling
Environmental DNA (eDNA) sampling is a valuable tool for ecological research, but its reliability as a quantitative approach can be improved by accounting for unexplained spatiotemporal variability and autocorrelation in eDNA concentrations. Sampling designs with temporal replication can separate sampling variation from temporal variation, but obtaining true temporal replicates is...
Authors
Ben C. Augustine, Patrick R. Hutchins, Scott D. George, Chany C. Huddleston Adrianza, Michael J. Darling, Thomas R. Sadekoski, Adam J. Sepulveda
Invasive hybridization has unpredicted and variable effects on trout survival in contrasting environments Invasive hybridization has unpredicted and variable effects on trout survival in contrasting environments
Invasive hybridization between native and introduced species is widespread, especially in fishes, yet its effects on fitness-related traits across environments remain poorly understood. We combined individual genetic admixture estimates with capture–recapture data to quantify how hybridization between native Westslope Cutthroat Trout (Oncorhynchus lewisi) and invasive Rainbow Trout...
Authors
Jeffrey T. Strait, Ryan P. Kovach, Lisa A Eby, Clint C. Muhlfeld, Matthew C. Boyer, Stephen J. Amish, Paul M. Luckas, Winsor H. Lowe, Gordon Luikart
Accounting for temporal variation and correlation in environmental DNA sampling can improve ecological inferences Accounting for temporal variation and correlation in environmental DNA sampling can improve ecological inferences
Environmental DNA (eDNA) concentration varies through space and time, and measurements collected close together are often correlated. Ignoring this dependence can inflate the rate of incorrect ecological inferences (Type I error rate). Although spatial correlation in eDNA has received considerable attention, temporal correlation has been less well studied. Statistical models and study...
Authors
Ben C. Augustine, Patrick R. Hutchins, Margaret E. Hunter, Christopher M. Merkes, David S. Pilliod, Stephen Frank Spear, Caitlin E. Beaver, Scott D. George, Devin Nicole Jones-Slobodian, Adam J. Sepulveda
Northern bobwhites select for native grasses on working grazing land Northern bobwhites select for native grasses on working grazing land
Northern bobwhite (Colinus virginianus; bobwhite) populations have experienced an 85% decline across most of its range since the 1960s. The most drastic decreases have been in the southeastern United States where biologists attribute the decline to widespread habitat loss, including conversion of native grasslands to tall fescue (Lolium arundinaceum) and other exotic cool-season grass...
Authors
Douglas B Mitchell, Patrick D. Keyser, Joseph D. Clark, David A. Buehler, James A Martin, Cody M. Rhoden, Bridgett Costanzo