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Daniel B. Fagre

Publications and source records attributed to Daniel B. Fagre.

At least 55 records · Page 3Linked to original sources
USGS2011

The unusual nature of recent snowpack declines in the North American cordillera

In western North America, snowpack has decl in ed in recent decades, and fur the r losses are projected through the 21st century. Here, we evaluate the uniqueness of recent declines us in g snowpack reconstructions from 66 tree-r in g chronologies in key run of f-generat in g areas of the Colorado, Columbia, and Missouri River dra in ages. Over the past millennium, late 20th century snowpack reductions are almost unprecedented in magnitude across the north ern Rocky Mounta in s and in the ir north -south synchrony across the cordillera . Both the snowpack declines and the ir synchrony result from unparalleled spr in gtime warm in g that is due to positive re in forcement of the anthropogenic warm in g by decadal variability. The in creas in g role of warm in g on large-scale snowpack variability and trends foreshadows fundamental impacts on streamflow and water supplies across the western United States.

Science↗
USGS2010

Avalanche 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 large magnitude avalanche cycle occurred in and around Glacier National Park, Montana. The study site is the Little Granite avalanche path located along the GTSR. The study is designed to quantify change in vegetative cover immediately after a large magnitude event and document ecological response over a multi-year period. GPS field mapping was completed to determine the redefined perimeter of the avalanche path. Vegetation was inventoried using modified U.S. Forest Service Forest Inventory and Analysis plots, cross sections were taken from over 100 dead trees throughout the avalanche path, and an avalanche chronology was developed. Initial results indicate that the perimeter of this path was expanded by 30%. The avalanche travelled approximately 1200 vertical meters and 3 linear kilometers. Stands of large conifers as old as 150 years were decimated by the avalanche, causing a shift in dominant vegetation types in many parts of the avalanche path. Woody debris is a major ground cover up to 3 m in depth on lower portions of the avalanche path and will likely affect tree regrowth. Monitoring and measuring the post-avalanche vegetation recovery of this particular avalanche path provides a unique dataset for determining the ecological role of avalanches in mountain landscapes.

Montana↗
USGS2010

A practitioner's tool for assessing glide crack activity

Glide cracks can result in full-depth glide avalanche release. Avalanches from glide cracks are notoriously difficult to forecast, but are a reoccurring problem in a number of different avalanche forecasting programs across a range of snow climates. Despite this, there is no consensus for how to best manage, mitigate, or even observe glide cracks and the potential resultant avalanche activity. It is thought that an increase in the rate of snow gliding occurs prior to full-depth avalanche activity, so frequent measuring of glide crack movement provides an index of instability. Therefore, a comprehensive avalanche program with glide crack avalanche activity, should at the least, undertake some form of direct monitoring of glide crack movement. In this paper we present a simple, cheap and repeatable method to track glide crack activity using a series of stakes, reflectors and a laser rangefinder (LaserTech TruPulse360B) linked to a GPS (Trimble Geo XH). We tested the methodology in April 2010, on a glide crack above the Going to the Sun Road in Glacier National Park, Montana, USA. This study suggests a new method to better track the development and movement of glide cracks. It is hoped that by introducing a workable method to easily record glide crack movement, avalanche forecasters will improve their understanding of when, or if, avalanche activity will ensue. Our initial results suggest that these new observations, when combined with local micrometeorological data will result in improved process understanding and forecasting of these phenomena.

Conference Paper↗
USGS2010

Using GIS and Google Earth for the creation of the Going-to-the-Sun Road Avalanche Atlas, Glacier National Park, Montana, USA

Snow avalanche paths are key geomorphologic features in Glacier National Park, Montana, and an important component of mountain ecosystems: they are isolated within a larger ecosystem, they are continuously disturbed, and they contain unique physical characteristics (Malanson and Butler, 1984). Avalanches impact subalpine forest structure and function, as well as overall biodiversity (Bebi et al., 2009). Because avalanches are dynamic phenomena, avalanche path geometry and spatial extent depend upon climatic regimes. The USGS/GNP Avalanche Program formally began in 2003 as an avalanche forecasting program for the spring opening of the ever-popular Going-to-the-Sun Road (GTSR), which crosses through 37 identified avalanche paths. Avalanche safety and forecasting is a necessary part of the GTSR spring opening procedures. An avalanche atlas detailing topographic parameters and oblique photographs was completed for the GTSR corridor in response to a request from GNP personnel for planning and resource management. Using ArcMap 9.2 GIS software, polygons were created for every avalanche path affecting the GTSR using aerial imagery, field-based observations, and GPS measurements of sub-meter accuracy. Spatial attributes for each path were derived within the GIS. Resulting products include an avalanche atlas book for operational use, a geoPDF of the atlas, and a Google Earth flyover illustrating each path and associated photographs. The avalanche atlas aids park management in worker safety, infrastructure planning, and natural resource protection by identifying avalanche path patterns and location. The atlas was created for operational and planning purposes and is also used as a foundation for research such as avalanche ecology projects and avalanche path runout modeling.

Conference Paper↗
USGS2010

Characterizing wet slab and glide slab avalanche occurrence along the Going-to-the-Sun Road, Glacier National Park, Montana, USA

Wet slab and glide slab snow avalanches are dangerous and yet can be particularly difficult to predict. Both wet slab and glide slab avalanches are thought to depend upon free water moving through the snowpack but are driven by different processes. In Glacier National Park, Montana, both types of avalanches can occur in the same year and affect the Going-to-the-Sun Road (GTSR). Both wet slab and glide slab avalanches along the GTSR from 2003-2010 are investigated. Meteorological data from two high-elevation weather stations and one SNOTEL site are used in conjunction with an avalanche database and snowpit profiles. These data were used to characterize years when only glide slab avalanches occurred and those years when both glide slab and wet slab avalanches occurred. Results of 168 glide slab and 57 wet slab avalanches along the GTSR suggest both types of avalanche occurrence depend on sustained warming periods with intense solar radiation (or rain on snow) to produce free water in the snowpack. Differences in temperature and net radiation metrics between wet slab and glide slab avalanches emerge as one moves from one day to seven days prior to avalanche occurrence. On average, a more rapid warming precedes wet slab avalanche occurrence. Glide slab and wet slab avalanches require a similar amount of net radiation. Wet slab avalanches do not occur every year, while glide slab avalanches occur annually. These results aim to enhance understanding of the required meteorological conditions for wet slab and glide slab avalanches and aid in improved wet snow avalanche forecasting.

Montana↗
USGS2009

Long-duration drought variability and impacts on ecosystem services: A case study from Glacier National Park, Montana

Instrumental climate records suggest that summer precipitation and winter snowpack in Glacier National Park (Glacier NP), Montana, vary significantly over decadal to multidecadal time scales. Because instrumental records for the region are limited to the twentieth century, knowledge of the range of variability associated with these moisture anomalies and their impacts on ecosystems and physical processes are limited. The authors developed a reconstruction of summer (June–August) moisture variability spanning a.d. 1540–2000 from a multispecies network of tree-ring chronologies in Glacier NP. Decadal-scale drought and pluvial regimes were defined as any event lasting 10 yr or greater, and the significance of each potential regime was assessed using intervention analysis. Intervention analysis prevents single intervening years of average or opposing moisture conditions from ending what was otherwise a sustained moisture regime. The reconstruction shows numerous decadal-scale shifts between persistent drought and wet events prior to the instrumental period (before a.d. 1900). Notable wet events include a series of three long-duration, high-magnitude pluvial regimes spanning the end of the Little Ice Age ( a.d. 1770–1840). Though the late-nineteenth century was marked by a series of >10 yr droughts, the single most severe dry event occurred in the early-twentieth century ( a.d. 1917–41). These decadal-scale dry and wet events, in conjunction with periods of high and low snowpack, have served as a driver of ecosystem processes such as forest fires and glacial dynamics in the Glacier NP region. Using a suite of paleoproxy reconstructions and information from previous studies examining the relationship between climate variability and natural processes, the authors explore how such persistent moisture anomalies affect the delivery of vital goods and services provided by Glacier NP and surrounding areas. These analyses show that regional water resources and tourism are particularly vulnerable to persistent moisture anomalies in the Glacier NP area. Many of these same decadal-scale wet and dry events were also seen among a wider network of hydroclimatic reconstructions along a north–south transect of the Rocky Mountains. Such natural climate variability can, in turn, have enormous impacts on the sustainable provision of natural resources over wide areas. Overall, these results highlight the susceptibility of goods and services provided by protected areas like Glacier NP to natural climate variability, and show that this susceptibility will likely be compounded by the effects of future human-induced climate change.

Montana↗
USGS2008

Mass balance of a cirque glacier in the U.S. Rocky Mountains

Glacier National Park, Montana, USA, contains 27 cirque glaciers, most less than 1 km 2 and together comprising about 17 km 2 . These glaciers lie at relatively low elevation (2000 – 3000 m a.s.l.) and latitude (48 o N) and have undergone dramatic retreat since the mid-nineteenth century, when an estimated 150 glaciers existed. Continuing volume losses and the disappearance of glaciers in recent decades are used as key indicators of regional warming. Here we present initial results from a long-term study initiated in 2005 on Sperry Glacier (48.6 o N, 113.75 o W), a 0.8 km 2 cirque glacier that has undergone an 80% reduction in size since the mid 1800s. We calculated seasonal and annual balances using the direct glaciological method augmented with data from an automated weather station adjacent to the glacier and data from a nearby automated snow pillow. The net annual balance averaged -1.0 m w. eq. for the 2005 and 2006 balance years. Specific balances showed significant transverse spatial variability due to site-specific processes that augment accumulation or mute ablation. These processes have a significant effect on the mass balance of the glacier. Proxy measures showed that the 2005 and 2006 balance years likely had very low accumulation or very high ablation, respectively, relative to other years in recent decades.

Montana↗
USGS2007

Modeling the biophysical impacts of global change in mountain biosphere reserves

Mountains and mountain societies provide a wide range of goods and services to humanity, but they are particularly sensitive to the effects of global environmental change. Thus, the definition of appropriate management regimes that maintain the multiple functions of mountain regions in a time of greatly changing climatic, economic, and societal drivers constitutes a significant challenge. Management decisions must be based on a sound understanding of the future dynamics of these systems. The present article reviews the elements required for an integrated effort to project the impacts of global change on mountain regions, and recommends tools that can be used at 3 scientific levels (essential, improved, and optimum). The proposed strategy is evaluated with respect to UNESCO's network of Mountain Biosphere Reserves (MBRs), with the intention of implementing it in other mountain regions as well. First, methods for generating scenarios of key drivers of global change are reviewed, including land use/land cover and climate change. This is followed by a brief review of the models available for projecting the impacts of these scenarios on (1) cryospheric systems, (2) ecosystem structure and diversity, and (3) ecosystem functions such as carbon and water relations. Finally, the cross-cutting role of remote sensing techniques is evaluated with respect to both monitoring and modeling efforts. We conclude that a broad range of techniques is available for both scenario generation and impact assessments, many of which can be implemented without much capacity building across many or even most MBRs. However, to foster implementation of the proposed strategy, further efforts are required to establish partnerships between scientists and resource managers in mountain areas.

Mountain Research and Development↗
USGS2007

Preface

No abstract available.

Rocky Mountains↗
USGS2007

Monitoring alpine plants for climate change: The North American GLORIA Project

Alpine Environments Globally, alpine environments are hotspots of biodiversity, often harboring higher diversity of plant species than corresponding areas at lower elevations. These regions are also likely to experience more severe and rapid change in climate than lowlands under conditions of anthropogenic warming (Theurillat & Guisan 2001; Halloy & Mark 2003; Pickering & Armstrong 2003). Such climatic effects are already being documented by instrumental monitoring in the few places in western North America where long-term climate stations are available at high elevations. New sites are being planned (see GCOS article, pg 15). Climate Change is augmenting concern for alpine vegetation because available habitat diminishes at increasingly higher elevations. This creates an “elevational squeeze,” whereby the geometry of mountain peaks means that escape routes to cooler environments uphill are dead ends for migrating alpine species. While monitoring and modeling efforts have begun to elucidate climate of alpine environments in North America, very little is known about corresponding responses of alpine plant species to changing climate. Indeed, for many mountain regions in the West, little information exists even about alpine plant distribution and abundance.

Mountain Views↗
USGS2007

Adapting to the reality of climate change at Glacier National Park, Montana, USA

The glaciers of Glacier National Park (GNP) are disappearing rapidly and likely will be gone by 2030. These alpine glaciers have been continuously present for approximately 7,000 years so their loss from GNP in another 25 years underscores the significance of current climate change. There are presently only 27 glaciers remaining of the 150 estimated to have existed when GNP was created in 1910. Mean annual temperature in GNP has increased 1.6°C during the past century, three times the global mean increase. The temperature increase has affected other parts of the mountain ecosystem, too. Snowpacks hold less water equivalent and melt 2+ weeks earlier in the spring. Forest growth rates have increased, alpine treelines have expanded upward and become denser, and subalpine meadows have been invaded by high elevation tree species. These latter responses can be mostly attributed to longer growing seasons and warmer temperatures. Ecosystem modeling of possible future changes in the GNP mountain environments suggest that increased tree growth rates and evapotranspiration will reduce soil moisture and streamflow. The drier forests, with more wood, will burn more frequently and with greater severity, leading to degradation in air quality and increased risk to people and infrastructure. Management of forest fires is an important issue in the arid western United States. In 2003, 13% of GNP’s 4,082 km 2 was burned in three large fires and numerous smaller fires. Managers can accomplish some of their goals, such as preserving threatened wildlife populations, by altering their management of fires. In 2003, intense efforts were successfully made to divert the fires away from valuable grizzly bear ( Ursus arctos horribilis ) habitat that contained huckleberry plants ( Vaccinium spp .) necessary to ensure bear survival through the winter.

Montana↗
USGS2007

Response of western mountain ecosystems to climatic variability and change: The Western Mountain Initiative

Mountain ecosystems within our national parks and other protected areas provide valuable goods and services such as clean water, biodiversity conservation, and recreational opportunities, but their potential responses to expected climatic changes are inadequately understood. The Western Mountain Initiative (WMI) is a collaboration of scientists whose research focuses on understanding and predicting responses of western mountain ecosystems to climatic variability and change. It is a legacy of the Global Change Research Program initiated by the National Park Service (NPS) in 1991 and continued by the U.S. Geological Survey (USGS) to this day as part of the U.S. Climate Change Science Program (http://www.climatescience.gov/). All WMI scientists are active participants in CIRMOUNT, and seek to further its goals.

Mountain Views↗
USGS2006

Natural glide slab avalanches, Glacier National Park, USA: A unique hazard and forecasting challenge

In a museum of avalanche phenomena, glide cracks and glide avalanches might be housed in the “strange but true” section. These oddities are uncommon in most snow climates and tend to be isolated to specific terrain features such as bedrock slabs. Many glide cracks never result in avalanches, and when they do, the wide range of time between crack formation and slab failure makes them highly unpredictable. Despite their relative rarity, glide cracks and glide avalanches pose a regular threat and complex forecasting challenge during the annual spring opening of the Going-to-the-Sun Road in Glacier National Park, U.S.A. During the 2006 season, a series of unusual glide cracks delayed snow removal operations by over a week and provided a unique opportunity to record detailed observations of glide avalanches and characterize their occurrence and associated weather conditions. Field observations were from snowpits, crown profiles and where possible, measurements of slab thickness, bed surface slope angle, substrate and other physical characteristics. Weather data were recorded at one SNOTEL site and two automated stations located from 0.6-10 km of observed glide slab avalanches. Nearly half (43%) of the 35 glide slab avalanches recorded were Class D2-2.5, with 15% Class D3-D3.5. The time between glide crack opening and failure ranged from 2 days to over six weeks, and the avalanches occurred in cycles associated with loss of snow water equivalent and spikes in temperature and radiation. We conclude with suggest ions for further study.

Montana↗