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Louis Sass, III

Glaciology, mass balance, mountain glacier dynamics, glacier response to climate forcing

Professional Experience

  • 2012 - Present        Physical Scientist, USGS Alaska Science Center

  • 2009 - 2011             Instructor, Alaska Pacific University, Glaciology and Glacier Travel field course

  • 2009 - 2012             Student Trainee, USGS Alaska Science Center

Education and Certifications

  • M.S.   2011      Alaska Pacific University, Anchorage, AK           Environmental Science

  • B.A.    2000    The Colorado College, Colorado Springs, CO      Geology

Affiliations and Memberships*

  • International Glaciological Society

  • American Geophysical Union

Honors and Awards

  • NASA Earth and space science fellowship, 2009-2011

Science and Products

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South Cascade Glacier, northwestern Washington State

Glaciers and Climate Project

Mountain glaciers are dynamic reservoirs of frozen water closely coupled to ecosystems and climate. Glacier change in North America has major socioeconomic impacts, including global sea level change, tourism disruption, natural hazard risk, fishery effects, and water resource alteration. Understanding and quantifying precise connections between glaciers and climate is critical to decision makers...
By
Climate Research and Development Program, Alaska Science Center
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Glaciers and Climate Project

Mountain glaciers are dynamic reservoirs of frozen water closely coupled to ecosystems and climate. Glacier change in North America has major socioeconomic impacts, including global sea level change, tourism disruption, natural hazard risk, fishery effects, and water resource alteration. Understanding and quantifying precise connections between glaciers and climate is critical to decision makers...
Learn More
link
A scientist prepares to extract a snow core from one of the Benchmark Glaciers.

Gulkana Glacier

Gulkana Glacier is located in the high-latitude continental climate regime of Alaska’s Delta Mountains. Glacier observations began at this site in 1966.
By
Climate Research and Development Program, Alaska Science Center
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Gulkana Glacier

Gulkana Glacier is located in the high-latitude continental climate regime of Alaska’s Delta Mountains. Glacier observations began at this site in 1966.
Learn More
link
Lemon Creek Glacier

Lemon Creek Glacier

Lemon Creek Glacier is located in the high-latitude maritime region of Alaska, at the southernmost tip of the Juneau Icefield. Glacier observations began at this site in 1953.
By
Climate Research and Development Program, Alaska Science Center
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Lemon Creek Glacier

Lemon Creek Glacier is located in the high-latitude maritime region of Alaska, at the southernmost tip of the Juneau Icefield. Glacier observations began at this site in 1953.
Learn More
link
A researcher gazes across Wolverine Glacier and the surrounding snow-covered mountains

Wolverine Glacier

Wolverine Glacier is located in the high-latitude maritime climate regime of Alaska’s Kenai Mountains. Glacier observations began at this site in 1966.
By
Climate Research and Development Program, Alaska Science Center
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Wolverine Glacier

Wolverine Glacier is located in the high-latitude maritime climate regime of Alaska’s Kenai Mountains. Glacier observations began at this site in 1966.
Learn More
link
Photograph looking across a large body of calm water surrounded by mountains with a glacier and snow-capped peaks in distance.

Assessing the Vulnerability of Alaska’s Glaciers in a Changing Climate

Retreating glaciers are an iconic image of climate change;yet not all glaciers in Alaska are actively retreating, and a few glaciers are even advancing. While this contrasting behavior can be misleading for the casual observer, variable responses between glaciers in a changing climate are expected. Glaciers act as conveyor belts that transport snow and ice from high elevations, where it does not m
By
Climate Adaptation Science Centers
link

Assessing the Vulnerability of Alaska’s Glaciers in a Changing Climate

Retreating glaciers are an iconic image of climate change;yet not all glaciers in Alaska are actively retreating, and a few glaciers are even advancing. While this contrasting behavior can be misleading for the casual observer, variable responses between glaciers in a changing climate are expected. Glaciers act as conveyor belts that transport snow and ice from high elevations, where it does not m
Learn More
link
Arctic glacier

USGS Benchmark Glacier Project

Scientists with the USGS Benchmark Glacier Project study the process and impacts of glacier change, including sea-level rise, water resources, environmental hazards and ecosystem links. At the core of this research are mass balance measurements at five glaciers in the United States. Since the 1960s, these glaciers have been studied using direct observations of glaciers and meteorology. The project...
By
Climate Research and Development Program
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USGS Benchmark Glacier Project

Scientists with the USGS Benchmark Glacier Project study the process and impacts of glacier change, including sea-level rise, water resources, environmental hazards and ecosystem links. At the core of this research are mass balance measurements at five glaciers in the United States. Since the 1960s, these glaciers have been studied using direct observations of glaciers and meteorology. The project...
Learn More
link
The "From Icefield to Ocean Poster" depicts the important linkages between glaciers and the ocean.

Wolverine Glacier Ecosystem Studies

This project is an extension of the long-term Wolverine Glacier Benchmark Glacier project and is improving our understanding of solutes and nutrients in glacier basins, and how they fuel downstream ecosystems.
By
Alaska Science Center
link

Wolverine Glacier Ecosystem Studies

This project is an extension of the long-term Wolverine Glacier Benchmark Glacier project and is improving our understanding of solutes and nutrients in glacier basins, and how they fuel downstream ecosystems.
Learn More

Firn Density and Stratigraphy Observations from USGS Benchmark Glaciers

This dataset contains observations of snow and firn density and stratigraphy from Site EC on Wolverine Glacier. Site EC is located in the accumulation zone on the northwest flank of the upper glacier at 1350m. Cores were recovered using a FELICS corer to approximately 25m depth at the end of the accumulation season and the end of ablation season starting in 2016. Additional cores were drilled thro
By
Alaska Science Center

USGS Benchmark Glacier Mass Balance and Project Data

Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Additional measurements have been made on Lemon Creek Glacier, AK to compliment data collected by the Juneau Icefield Research
By
Alaska Science Center

Point Raw Glaciological Data: Ablation Stake, Snow Pit, and Probed Snow Depth Data on USGS Benchmark Glaciers

Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Additional measurements have been made on Lemon Creek and Taku glaciers, AK to compliment data collected by the Juneau Icefield
By
Climate Research and Development Program, Alaska Science Center

Geodetic Data for USGS Benchmark Glaciers: Orthophotos, Digital Elevation Models, Glacier Boundaries and Surveyed Positions

Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Additional measurements have been made on Lemon Creek Glacier, AK to compliment data collected by the Juneau Icefield Research
By
Climate Research and Development Program, Alaska Science Center

Glacier-Wide Mass Balance and Compiled Data Inputs: USGS Benchmark Glaciers

Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Additional measurements have been made on Lemon Creek Glacier, AK to compliment data collected by the Juneau Icefield Research
By
Climate Research and Development Program, Alaska Science Center

Raw Ground Penetrating Radar Data on North American Glaciers

U.S. Geological Survey researchers conducted time-series ground-penetrating radar (GPR) surveys with a Sensors and Software 500-MHz Pulse Ekko Pro system. This data release contains ground-based (ski and snowmobile) as well as airborne common-offset profiles. All profiles are linked to coincident GPS observations. Additionally, common-midpoint data was collected at specific glacier locations. Coin
By
Alaska Science Center

High Altitude Weather Station Data at USGS Benchmark Glaciers

Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Additional measurements have been made on Lemon Creek Glacier, AK to compliment data collected by the Juneau Icefield Research
By
Alaska Science Center
Filter Total Items: 29
Remote weather station at Wolverine Glacier, Alaska. The sun is setting with an almost full moon in the sky.
link
Female wearing safety gear, using radio-echo-sounding, and entering data on handheld computer on Wolverine Glacier.
link
Weighing type precipitation gage is on the left and new radar-based sensor in on a pole on the right
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The new radar-based precipitation sensor is on the left, with the anemometer, wind vane, and GOES antenna on the station shack
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Close up of the new radar precipitation sensor on the top of the pole at Wolverine Glacier, Alaska
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Wolverine Glacier weather station in the Kenai Mountains on the coast of south-central Alaska
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Ablation stakes on Gulkana Glacier. Late summer fieldwork on Gulkana Glacier reveals ablation stakes emerging from the ice.
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Gulkana Glacier weather station
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USGS scientist, measures and weighs an ice core extracted from Wolverine Glacier.
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A scientist prepares to extract a snow core from one of the Benchmark Glaciers.
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Three USGS researchers use ground penetrating radar to determine the depth of the snow on Wolverine Glacier, AK
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A researcher locates an ablation stake near a crevasse on Wolverine Glacier
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USGS scientist, examines a full firn core taken on Wolverine Glacier in Alaska.
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USGS scientist, Chris McNeil, collects data at an ablation stake on Wolverine Glacier, AK
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Gulkana Glacier
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Gulkana Glacier
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Heavily crevassed terminus of Gulkana Glacier, AK
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A scientist dumps DNA tracer into a moulin on Wolverine Glacier to assess water flow through the glacier.
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Scientist holding an ablation stake on glacier. These stakes are used to probe snow on a glacier to determine snow depth.
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close up of a snow core. The layers that make up snow cores are measured to determine the density of the snow and ice.
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South Cascade Glacier, northwestern Washington State
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Uncertainty of ICESat-2 ATL06- and ATL08-derived snow depths for glacierized and vegetated mountain regions

Seasonal snow melt dominates the hydrologic budget across a large portion of the globe. Snow accumulation and melt vary over a broad range of spatial scales, preventing accurate extrapolation of sparse in situ observations to watershed scales. The lidar onboard the Ice, Cloud, and land Elevation, Satellite (ICESat-2) was designed for precise mapping of ice sheets and sea ice, and here we assess th
Authors
Ellyn Enderlin, Colten Elkin, Madeline Gendreau, H. P. Marshall, Shad O'Neel, Christopher J. McNeil, Caitlyn Florentine, Louis C. Sass
By
Ecosystems Mission Area, Northern Rocky Mountain Science Center

Beyond glacier-wide mass balances: Parsing seasonal elevation change into spatially resolved patterns of accumulation and ablation at Wolverine Glacier, Alaska

We present spatially distributed seasonal and annual surface mass balances of Wolverine Glacier, Alaska, from 2016 to 2020. Our approach accounts for the effects of ice emergence and firn compaction on surface elevation changes to resolve the spatial patterns in mass balance at 10 m scale. We present and compare three methods for estimating emergence velocities. Firn compaction was constrained by
Authors
Lucas Zeller, Daniel J McGrath, Louis C. Sass, Shad O'Neel, Christopher J. McNeil, Emily Baker
By
Climate Research and Development Program, Alaska Science Center

The imminent calving retreat of Taku Glacier

Along the rugged Southeast Alaska coast, 30 kilometers northeast of the state capital Juneau, a tidewater glacier has largely defied global trends by steadily advancing for most of the past century while most glaciers on Earth retreated. This 55-kilometer-long and nearly 1,500-meter-thick tidewater glacier, named Taku Glacier, or T'aaḵú Ḵwáan Sít'i in the language of the Indigenous Tlingit people,
Authors
Christopher J. McNeil, Jason Amundson, Shad O'Neel, Roman Motyka, Louis C. Sass, Martin Truffer, Jenna Ziemann, Seth Campbell
By
Climate Research and Development Program, Land Change Science Program, Alaska Science Center

Explaining mass balance and retreat dichotomies at Taku and Lemon Creek Glaciers, Alaska

We reanalyzed mass balance records at Taku and Lemon Creek Glaciers to better understand the relative roles of hypsometry, local climate and dynamics as mass balance drivers. Over the 1946–2018 period, the cumulative mass balances diverged. Tidewater Taku Glacier advanced and gained mass at an average rate of +0.25±0.28 m w.e. a–1, contrasting with retreat and mass loss of –0.60±0.15 m w.e. a-1 at
Authors
Christopher J. McNeil, Shad O'Neel, Michael Loso, Mauri Pelto, Louis C. Sass, Emily Baker, Seth Campbell
By
Climate Research and Development Program, Land Change Science Program, Alaska Science Center

Reanalysis of the U.S. Geological Survey Benchmark Glaciers: Long-term insight into climate forcing of glacier mass balance

Mountain glaciers integrate climate processes to provide an unmatched signal of regional climate forcing. However, extracting the climate signal via intercomparison of regional glacier mass balance records can be problematic when methods for extrapolating and calibrating direct glaciological measurements are mixed or inconsistent. To address this problem, we reanalyzed and compared long-term mass
Authors
Shad O'Neel, Christopher J. McNeil, Louis C. Sass, Caitlyn Florentine, Emily Baker, Erich Peitzsch, Daniel J McGrath, Andrew G. Fountain, Daniel B. Fagre
By
Climate Research and Development Program, Land Change Science Program, Alaska Science Center

Snow and ice

Temperature and precipitation are key determinants of snowpack levels. Therefore, climate change is likely to affect the role of snow and ice in the landscapes and hydrology of the Chugach National Forest region.Downscaled climate projections developed by Scenarios Network for Alaska and Arctic Planning (SNAP) are useful for examining projected changes in snow at relatively fine resolution using a
Authors
Jeremy S. Littell, Stephanie A. McAfee, Shad O'Neel, Louis C. Sass, Evan Burgess, Steve Colt, Paul Clark
By
Ecosystems Mission Area, Climate Adaptation Science Centers

Geometry, mass balance and thinning at Eklutna Glacier, Alaska: an altitude-mass-balance feedback with implications for water resources

We analyzed glacier surface elevations (1957, 2010 and 2015) and surface mass-balance measurements (2008–2015) on the 30 km2 Eklutna Glacier, in the Chugach Mountains of southcentral Alaska. The geodetic mass balances from 1957 to 2010 and 2010 to 2015 are −0.52 ± 0.46 and −0.74 ± 0.10 m w.e. a−1, respectively. The glaciological mass balance of −0.73 m w.e. a−1 from 2010 to 2015 is indistinguishab
Authors
Louis C. Sass, Michael G. Loso, Jason Geck, Evan Thoms, Daniel Mcgrath
By
Alaska Science Center

Hypsometric control on glacier mass balance sensitivity in Alaska and northwest Canada

Glacier hypsometry provides a first‐order approach for assessing a glacier's response to climate forcings. We couple the Randolph Glacier Inventory to a suite of in situ observations and climate model output to examine potential change for the ∼27,000 glaciers in Alaska and northwest Canada through the end of the 21st century. By 2100, based on Representative Concentration Pathways (RCPs) 4.5–8.5
Authors
Daniel Mcgrath, Louis C. Sass, Shad O'Neel, Anthony A. Arendt, C. Kienholz
By
Ecosystems Mission Area, Alaska Science Center

End-of-winter snow depth variability on glaciers in Alaska

A quantitative understanding of snow thickness and snow water equivalent (SWE) on glaciers is essential to a wide range of scientific and resource management topics. However, robust SWE estimates are observationally challenging, in part because SWE can vary abruptly over short distances in complex terrain due to interactions between topography and meteorological processes. In spring 2013, we measu
Authors
Daniel Mcgrath, Louis C. Sass, Shad O'Neel, Anthony Arendt, Gabriel Wolken, Alessio Gusmeroli, Christian Kienholz, Christopher J. McNeil
By
Alaska Science Center

Assessing streamflow sensitivity to variations in glacier mass balance

The mountains ringing the Gulf of Alaska (GOA) receive upwards of 4–8 m yr−1 of precipitation (Simpson et al.2005; Weingartner et al. 2005; O’Neel 2012), much of which runs off into productive coastal waters. The alpine landscape is heavily glacierized, and storage and turnover of water by glaciers substantially influences the regional surface water balance (Neal et al. 2010). In turn, the land-to
Authors
Shad O'Neel, Eran Hood, Anthony Arendt, Louis C. Sass
By
Alaska Science Center

Re-analysis of Alaskan benchmark glacier mass-balance data using the index method

At Gulkana and Wolverine Glaciers, designated the Alaskan benchmark glaciers, we re-analyzed and re-computed the mass balance time series from 1966 to 2009 to accomplish our goal of making more robust time series. Each glacier's data record was analyzed with the same methods. For surface processes, we estimated missing information with an improved degree-day model. Degree-day models predict ablati
Authors
Ashely E. Van Beusekom, Shad R. O'Nell, Rod S. March, Louis C. Sass, Leif H. Cox
By
Alaska Science Center

Non-USGS Publications**

Sugden, D. E., G. A. Balco, S. G. Cowdery, J. O. Stone, and L. C. Sass. 2005. Selective glacial erosion and weathering zones in the coastal mountains of Marie Byrd Land, Antarctica. Geomorphology 67:317-334. doi:10.1016/j.geomorph.2004.10.007
Siddoway, C. S., L. C. Sass, and R. P. Esser. 2005. Kinematic history of western Marie Byrd Land, West Antarctica: Direct evidence from Cretaceous mafic dykes. Geological Society, London, Special Publications 246:417-438. doi:10.1144/GSL.SP.2005.246.01.17
Stone, J. O., G. A. Balco, D. E. Sugden, M. W. Caffee, L. C. Sass, S. G. Cowdery, and C. S. Siddoway. 2003. Holocene deglaciation of Marie Byrd Land, West Antarctica. Science 299(5603):99-102. doi:10.1126/science.1077998
McGrath, D. , Sass, L. , O'Neel, S. , Arendt, A. and Kienholz, C. (2017), Hypsometric control on glacier mass balance sensitivity in Alaska and northwest Canada. Earth's Future, 5: 324-336. doi:10.1002/2016EF000479

**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.

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Beautiful geonarrative published about decades old USGS Benchmark Glacier Project

A new, beautiful geonarrative titled “The Glacier-Climate Connection” describes the USGS Benchmark Glacier Project— one of the longest running studies...

Read Article
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Video Interviews about Glaciers

Video interviews about ongoing USGS glacier research were featured on the FOX Weather channel. The two videos feature Alaska Science Center scientist...

Read Article

Science and Products

  • Science
    link
    South Cascade Glacier, northwestern Washington State

    Glaciers and Climate Project

    Mountain glaciers are dynamic reservoirs of frozen water closely coupled to ecosystems and climate. Glacier change in North America has major socioeconomic impacts, including global sea level change, tourism disruption, natural hazard risk, fishery effects, and water resource alteration. Understanding and quantifying precise connections between glaciers and climate is critical to decision makers...
    By
    Climate Research and Development Program, Alaska Science Center
    link

    Glaciers and Climate Project

    Mountain glaciers are dynamic reservoirs of frozen water closely coupled to ecosystems and climate. Glacier change in North America has major socioeconomic impacts, including global sea level change, tourism disruption, natural hazard risk, fishery effects, and water resource alteration. Understanding and quantifying precise connections between glaciers and climate is critical to decision makers...
    Learn More
    link
    A scientist prepares to extract a snow core from one of the Benchmark Glaciers.

    Gulkana Glacier

    Gulkana Glacier is located in the high-latitude continental climate regime of Alaska’s Delta Mountains. Glacier observations began at this site in 1966.
    By
    Climate Research and Development Program, Alaska Science Center
    link

    Gulkana Glacier

    Gulkana Glacier is located in the high-latitude continental climate regime of Alaska’s Delta Mountains. Glacier observations began at this site in 1966.
    Learn More
    link
    Lemon Creek Glacier

    Lemon Creek Glacier

    Lemon Creek Glacier is located in the high-latitude maritime region of Alaska, at the southernmost tip of the Juneau Icefield. Glacier observations began at this site in 1953.
    By
    Climate Research and Development Program, Alaska Science Center
    link

    Lemon Creek Glacier

    Lemon Creek Glacier is located in the high-latitude maritime region of Alaska, at the southernmost tip of the Juneau Icefield. Glacier observations began at this site in 1953.
    Learn More
    link
    A researcher gazes across Wolverine Glacier and the surrounding snow-covered mountains

    Wolverine Glacier

    Wolverine Glacier is located in the high-latitude maritime climate regime of Alaska’s Kenai Mountains. Glacier observations began at this site in 1966.
    By
    Climate Research and Development Program, Alaska Science Center
    link

    Wolverine Glacier

    Wolverine Glacier is located in the high-latitude maritime climate regime of Alaska’s Kenai Mountains. Glacier observations began at this site in 1966.
    Learn More
    link
    Photograph looking across a large body of calm water surrounded by mountains with a glacier and snow-capped peaks in distance.

    Assessing the Vulnerability of Alaska’s Glaciers in a Changing Climate

    Retreating glaciers are an iconic image of climate change;yet not all glaciers in Alaska are actively retreating, and a few glaciers are even advancing. While this contrasting behavior can be misleading for the casual observer, variable responses between glaciers in a changing climate are expected. Glaciers act as conveyor belts that transport snow and ice from high elevations, where it does not m
    By
    Climate Adaptation Science Centers
    link

    Assessing the Vulnerability of Alaska’s Glaciers in a Changing Climate

    Retreating glaciers are an iconic image of climate change;yet not all glaciers in Alaska are actively retreating, and a few glaciers are even advancing. While this contrasting behavior can be misleading for the casual observer, variable responses between glaciers in a changing climate are expected. Glaciers act as conveyor belts that transport snow and ice from high elevations, where it does not m
    Learn More
    link
    Arctic glacier

    USGS Benchmark Glacier Project

    Scientists with the USGS Benchmark Glacier Project study the process and impacts of glacier change, including sea-level rise, water resources, environmental hazards and ecosystem links. At the core of this research are mass balance measurements at five glaciers in the United States. Since the 1960s, these glaciers have been studied using direct observations of glaciers and meteorology. The project...
    By
    Climate Research and Development Program
    link

    USGS Benchmark Glacier Project

    Scientists with the USGS Benchmark Glacier Project study the process and impacts of glacier change, including sea-level rise, water resources, environmental hazards and ecosystem links. At the core of this research are mass balance measurements at five glaciers in the United States. Since the 1960s, these glaciers have been studied using direct observations of glaciers and meteorology. The project...
    Learn More
    link
    The "From Icefield to Ocean Poster" depicts the important linkages between glaciers and the ocean.

    Wolverine Glacier Ecosystem Studies

    This project is an extension of the long-term Wolverine Glacier Benchmark Glacier project and is improving our understanding of solutes and nutrients in glacier basins, and how they fuel downstream ecosystems.
    By
    Alaska Science Center
    link

    Wolverine Glacier Ecosystem Studies

    This project is an extension of the long-term Wolverine Glacier Benchmark Glacier project and is improving our understanding of solutes and nutrients in glacier basins, and how they fuel downstream ecosystems.
    Learn More
  • Data

    Firn Density and Stratigraphy Observations from USGS Benchmark Glaciers

    This dataset contains observations of snow and firn density and stratigraphy from Site EC on Wolverine Glacier. Site EC is located in the accumulation zone on the northwest flank of the upper glacier at 1350m. Cores were recovered using a FELICS corer to approximately 25m depth at the end of the accumulation season and the end of ablation season starting in 2016. Additional cores were drilled thro
    By
    Alaska Science Center

    USGS Benchmark Glacier Mass Balance and Project Data

    Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Additional measurements have been made on Lemon Creek Glacier, AK to compliment data collected by the Juneau Icefield Research
    By
    Alaska Science Center

    Point Raw Glaciological Data: Ablation Stake, Snow Pit, and Probed Snow Depth Data on USGS Benchmark Glaciers

    Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Additional measurements have been made on Lemon Creek and Taku glaciers, AK to compliment data collected by the Juneau Icefield
    By
    Climate Research and Development Program, Alaska Science Center

    Geodetic Data for USGS Benchmark Glaciers: Orthophotos, Digital Elevation Models, Glacier Boundaries and Surveyed Positions

    Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Additional measurements have been made on Lemon Creek Glacier, AK to compliment data collected by the Juneau Icefield Research
    By
    Climate Research and Development Program, Alaska Science Center

    Glacier-Wide Mass Balance and Compiled Data Inputs: USGS Benchmark Glaciers

    Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Additional measurements have been made on Lemon Creek Glacier, AK to compliment data collected by the Juneau Icefield Research
    By
    Climate Research and Development Program, Alaska Science Center

    Raw Ground Penetrating Radar Data on North American Glaciers

    U.S. Geological Survey researchers conducted time-series ground-penetrating radar (GPR) surveys with a Sensors and Software 500-MHz Pulse Ekko Pro system. This data release contains ground-based (ski and snowmobile) as well as airborne common-offset profiles. All profiles are linked to coincident GPS observations. Additionally, common-midpoint data was collected at specific glacier locations. Coin
    By
    Alaska Science Center

    High Altitude Weather Station Data at USGS Benchmark Glaciers

    Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Additional measurements have been made on Lemon Creek Glacier, AK to compliment data collected by the Juneau Icefield Research
    By
    Alaska Science Center
  • Multimedia
    Filter Total Items: 29
    Remote weather station at Wolverine Glacier, Alaska. The sun is setting with an almost full moon in the sky.
    link
    Female wearing safety gear, using radio-echo-sounding, and entering data on handheld computer on Wolverine Glacier.
    link
    Weighing type precipitation gage is on the left and new radar-based sensor in on a pole on the right
    link
    The new radar-based precipitation sensor is on the left, with the anemometer, wind vane, and GOES antenna on the station shack
    link
    Close up of the new radar precipitation sensor on the top of the pole at Wolverine Glacier, Alaska
    link
    Wolverine Glacier weather station in the Kenai Mountains on the coast of south-central Alaska
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    Ablation stakes on Gulkana Glacier. Late summer fieldwork on Gulkana Glacier reveals ablation stakes emerging from the ice.
    link
    Gulkana Glacier weather station
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    USGS scientist, measures and weighs an ice core extracted from Wolverine Glacier.
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    A scientist prepares to extract a snow core from one of the Benchmark Glaciers.
    link
    Three USGS researchers use ground penetrating radar to determine the depth of the snow on Wolverine Glacier, AK
    link
    A researcher locates an ablation stake near a crevasse on Wolverine Glacier
    link
    USGS scientist, examines a full firn core taken on Wolverine Glacier in Alaska.
    link
    USGS scientist, Chris McNeil, collects data at an ablation stake on Wolverine Glacier, AK
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    Gulkana Glacier
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    Gulkana Glacier
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    Heavily crevassed terminus of Gulkana Glacier, AK
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    A scientist dumps DNA tracer into a moulin on Wolverine Glacier to assess water flow through the glacier.
    link
    Scientist holding an ablation stake on glacier. These stakes are used to probe snow on a glacier to determine snow depth.
    link
    close up of a snow core. The layers that make up snow cores are measured to determine the density of the snow and ice.
    link
    South Cascade Glacier, northwestern Washington State
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  • Publications

    Uncertainty of ICESat-2 ATL06- and ATL08-derived snow depths for glacierized and vegetated mountain regions

    Seasonal snow melt dominates the hydrologic budget across a large portion of the globe. Snow accumulation and melt vary over a broad range of spatial scales, preventing accurate extrapolation of sparse in situ observations to watershed scales. The lidar onboard the Ice, Cloud, and land Elevation, Satellite (ICESat-2) was designed for precise mapping of ice sheets and sea ice, and here we assess th
    Authors
    Ellyn Enderlin, Colten Elkin, Madeline Gendreau, H. P. Marshall, Shad O'Neel, Christopher J. McNeil, Caitlyn Florentine, Louis C. Sass
    By
    Ecosystems Mission Area, Northern Rocky Mountain Science Center

    Beyond glacier-wide mass balances: Parsing seasonal elevation change into spatially resolved patterns of accumulation and ablation at Wolverine Glacier, Alaska

    We present spatially distributed seasonal and annual surface mass balances of Wolverine Glacier, Alaska, from 2016 to 2020. Our approach accounts for the effects of ice emergence and firn compaction on surface elevation changes to resolve the spatial patterns in mass balance at 10 m scale. We present and compare three methods for estimating emergence velocities. Firn compaction was constrained by
    Authors
    Lucas Zeller, Daniel J McGrath, Louis C. Sass, Shad O'Neel, Christopher J. McNeil, Emily Baker
    By
    Climate Research and Development Program, Alaska Science Center

    The imminent calving retreat of Taku Glacier

    Along the rugged Southeast Alaska coast, 30 kilometers northeast of the state capital Juneau, a tidewater glacier has largely defied global trends by steadily advancing for most of the past century while most glaciers on Earth retreated. This 55-kilometer-long and nearly 1,500-meter-thick tidewater glacier, named Taku Glacier, or T'aaḵú Ḵwáan Sít'i in the language of the Indigenous Tlingit people,
    Authors
    Christopher J. McNeil, Jason Amundson, Shad O'Neel, Roman Motyka, Louis C. Sass, Martin Truffer, Jenna Ziemann, Seth Campbell
    By
    Climate Research and Development Program, Land Change Science Program, Alaska Science Center

    Explaining mass balance and retreat dichotomies at Taku and Lemon Creek Glaciers, Alaska

    We reanalyzed mass balance records at Taku and Lemon Creek Glaciers to better understand the relative roles of hypsometry, local climate and dynamics as mass balance drivers. Over the 1946–2018 period, the cumulative mass balances diverged. Tidewater Taku Glacier advanced and gained mass at an average rate of +0.25±0.28 m w.e. a–1, contrasting with retreat and mass loss of –0.60±0.15 m w.e. a-1 at
    Authors
    Christopher J. McNeil, Shad O'Neel, Michael Loso, Mauri Pelto, Louis C. Sass, Emily Baker, Seth Campbell
    By
    Climate Research and Development Program, Land Change Science Program, Alaska Science Center

    Reanalysis of the U.S. Geological Survey Benchmark Glaciers: Long-term insight into climate forcing of glacier mass balance

    Mountain glaciers integrate climate processes to provide an unmatched signal of regional climate forcing. However, extracting the climate signal via intercomparison of regional glacier mass balance records can be problematic when methods for extrapolating and calibrating direct glaciological measurements are mixed or inconsistent. To address this problem, we reanalyzed and compared long-term mass
    Authors
    Shad O'Neel, Christopher J. McNeil, Louis C. Sass, Caitlyn Florentine, Emily Baker, Erich Peitzsch, Daniel J McGrath, Andrew G. Fountain, Daniel B. Fagre
    By
    Climate Research and Development Program, Land Change Science Program, Alaska Science Center

    Snow and ice

    Temperature and precipitation are key determinants of snowpack levels. Therefore, climate change is likely to affect the role of snow and ice in the landscapes and hydrology of the Chugach National Forest region.Downscaled climate projections developed by Scenarios Network for Alaska and Arctic Planning (SNAP) are useful for examining projected changes in snow at relatively fine resolution using a
    Authors
    Jeremy S. Littell, Stephanie A. McAfee, Shad O'Neel, Louis C. Sass, Evan Burgess, Steve Colt, Paul Clark
    By
    Ecosystems Mission Area, Climate Adaptation Science Centers

    Geometry, mass balance and thinning at Eklutna Glacier, Alaska: an altitude-mass-balance feedback with implications for water resources

    We analyzed glacier surface elevations (1957, 2010 and 2015) and surface mass-balance measurements (2008–2015) on the 30 km2 Eklutna Glacier, in the Chugach Mountains of southcentral Alaska. The geodetic mass balances from 1957 to 2010 and 2010 to 2015 are −0.52 ± 0.46 and −0.74 ± 0.10 m w.e. a−1, respectively. The glaciological mass balance of −0.73 m w.e. a−1 from 2010 to 2015 is indistinguishab
    Authors
    Louis C. Sass, Michael G. Loso, Jason Geck, Evan Thoms, Daniel Mcgrath
    By
    Alaska Science Center

    Hypsometric control on glacier mass balance sensitivity in Alaska and northwest Canada

    Glacier hypsometry provides a first‐order approach for assessing a glacier's response to climate forcings. We couple the Randolph Glacier Inventory to a suite of in situ observations and climate model output to examine potential change for the ∼27,000 glaciers in Alaska and northwest Canada through the end of the 21st century. By 2100, based on Representative Concentration Pathways (RCPs) 4.5–8.5
    Authors
    Daniel Mcgrath, Louis C. Sass, Shad O'Neel, Anthony A. Arendt, C. Kienholz
    By
    Ecosystems Mission Area, Alaska Science Center

    End-of-winter snow depth variability on glaciers in Alaska

    A quantitative understanding of snow thickness and snow water equivalent (SWE) on glaciers is essential to a wide range of scientific and resource management topics. However, robust SWE estimates are observationally challenging, in part because SWE can vary abruptly over short distances in complex terrain due to interactions between topography and meteorological processes. In spring 2013, we measu
    Authors
    Daniel Mcgrath, Louis C. Sass, Shad O'Neel, Anthony Arendt, Gabriel Wolken, Alessio Gusmeroli, Christian Kienholz, Christopher J. McNeil
    By
    Alaska Science Center

    Assessing streamflow sensitivity to variations in glacier mass balance

    The mountains ringing the Gulf of Alaska (GOA) receive upwards of 4–8 m yr−1 of precipitation (Simpson et al.2005; Weingartner et al. 2005; O’Neel 2012), much of which runs off into productive coastal waters. The alpine landscape is heavily glacierized, and storage and turnover of water by glaciers substantially influences the regional surface water balance (Neal et al. 2010). In turn, the land-to
    Authors
    Shad O'Neel, Eran Hood, Anthony Arendt, Louis C. Sass
    By
    Alaska Science Center

    Re-analysis of Alaskan benchmark glacier mass-balance data using the index method

    At Gulkana and Wolverine Glaciers, designated the Alaskan benchmark glaciers, we re-analyzed and re-computed the mass balance time series from 1966 to 2009 to accomplish our goal of making more robust time series. Each glacier's data record was analyzed with the same methods. For surface processes, we estimated missing information with an improved degree-day model. Degree-day models predict ablati
    Authors
    Ashely E. Van Beusekom, Shad R. O'Nell, Rod S. March, Louis C. Sass, Leif H. Cox
    By
    Alaska Science Center

    Non-USGS Publications**

    Sugden, D. E., G. A. Balco, S. G. Cowdery, J. O. Stone, and L. C. Sass. 2005. Selective glacial erosion and weathering zones in the coastal mountains of Marie Byrd Land, Antarctica. Geomorphology 67:317-334. doi:10.1016/j.geomorph.2004.10.007
    Siddoway, C. S., L. C. Sass, and R. P. Esser. 2005. Kinematic history of western Marie Byrd Land, West Antarctica: Direct evidence from Cretaceous mafic dykes. Geological Society, London, Special Publications 246:417-438. doi:10.1144/GSL.SP.2005.246.01.17
    Stone, J. O., G. A. Balco, D. E. Sugden, M. W. Caffee, L. C. Sass, S. G. Cowdery, and C. S. Siddoway. 2003. Holocene deglaciation of Marie Byrd Land, West Antarctica. Science 299(5603):99-102. doi:10.1126/science.1077998
    McGrath, D. , Sass, L. , O'Neel, S. , Arendt, A. and Kienholz, C. (2017), Hypsometric control on glacier mass balance sensitivity in Alaska and northwest Canada. Earth's Future, 5: 324-336. doi:10.1002/2016EF000479

    **Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.

  • News
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    Beautiful geonarrative published about decades old USGS Benchmark Glacier Project

    A new, beautiful geonarrative titled “The Glacier-Climate Connection” describes the USGS Benchmark Glacier Project— one of the longest running studies...

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    Video Interviews about Glaciers

    Video interviews about ongoing USGS glacier research were featured on the FOX Weather channel. The two videos feature Alaska Science Center scientist...

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*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government