Scientist working on Sperry Glacier in Glacier National Park, Montana. Sperry Glacier occupies a broad, shallow cirque situated just beneath and west of the Continental Divide in the Lewis Mountain Range of Glacier National Park, Montana. Due to its position on the Continental Divide the glacier is influenced by both maritime and continental air masses.
Sperry Glacier is located along the Continental Divide within Glacier National Park, Montana. It represents the midlatitude continental or transitional climate. Glacier observations began at this site in 2005.
Return to Glaciers and Climate Project
Sources/Usage: Public Domain. View Media Details
Sperry Glacier occupies a broad, shallow cirque situated just beneath and west of the Continental Divide in the Lewis Mountain Range of Glacier National Park, Montana. This northeast facing glacier is wider than it is long relative to its flow direction and spans about 300 m in elevation with a median altitude of 2450 m. It ranks as a moderately sized glacier for this region, which contains the second highest concentration of glaciers in the U.S. Rocky Mountains. The glacier is in a ~4 km2 hanging cirque, and in 2014 it had an area of 0.80 km2, making Sperry Glacier the smallest of the benchmark glaciers.
Due to its position on the Continental Divide the glacier is influenced by both maritime and continental air masses. However, given its position on the western and predominantly windward side of the Continental Divide, Pacific storm systems dominate the weather. These bring heavy precipitation and moderate temperatures as warm, moist Pacific fronts collide with and lift over the Rocky Mountains. Temperature and precipitation patterns in northwest Montana are marked by strong altitudinal gradients. For valley sites at about 1000 m, mean temperatures for July, which is generally the warmest month of the year, are typically 15-17°C (59-63°F); they are roughly half that for mountain sites at 2500 m (Finklin, 1986). Annual precipitation averages 580 mm on the western and eastern edges of Glacier Park, but over 2500 mm at higher elevations in the Park's interior near the Continental Divide.
In 2005, the USGS Climate Change in Mountain Ecosystems (CCME) program established a glacier monitoring strategy in northwest Montana with the goal of assessing long-term changes to the region's glaciers. Through this monitoring program researchers also aimed to evaluate the hydrologic and ecologic effects of glaciers in Glacier National Park. Sperry Glacier was chosen as the benchmark study glacier due to its history of previous research, physical characteristics, and accessibility.
Research
Sources/Usage: Public Domain. View Media Details
Glacier mass balance
Sources/Usage: Public Domain. View Media Details
Sperry became the focus of extensive field research starting in 2005 as scientists employed standard glaciological methods (Ostrem and Brugman, 1991) to estimate glacier-wide seasonal and annual surface mass balances. Snow depths and densities are measured in the spring when the glacier's balance is at a maximum. Ablation stakes are also installed at this time and then checked periodically during the summer melt season with a final check in early autumn at the balance minima. With similar goals and methodologies, the Sperry Glacier mass balance project joined the established USGS Benchmark Program in 2013. The addition of Sperry to the long-established mass balance monitoring projects in Alaska and Washington will facilitate a broader understanding of glacier dynamics, hydrology, and glacier response to climate change.
Direct field measurements are combined with weather data and imagery analyses to calculate the seasonal and annual mass balance of each glacier. Access all the data here.
Meteorologic
In June 2006 the Sperry Glacier weather station (48° 37' 24.1932" N, 113° 45' 53.4347" W) was installed at an altitude of 2450 m on a rocky outcrop about 100 m from the western edge of the glacier. Sensors measured air temperature, wind speed and direction, incoming solar radiation, and relative humidity. It became apparent that the 2 m mast height was not sufficient as the station was buried every winter and typically did not melt out until June. In some years the sensors were damaged so severely by snowpack creep that they needed replacing. During years with exceptionally heavy snowfall, such as in 2011, the station did not melt out until late July. The station was abandoned in 2012 due to these issues and there are no data for that year. But in 2013, the station was re-installed and recorded data for most of the June through September ablation season. In September 2014 a new station was installed in the same location with a 4 m mast and fitted with new instruments including a net radiometer, a new power system, and satellite telemetry. The taller mast should keep the sensors above the snowpack surface during the winter allowing the station to remain operational year round.
There are complete records of daily average temperature for the months July and August 2006-2011 and 2013. Most of the ablation on the glacier occurs during these two summer months. For the period of record, the mean July-August daily average temperature was 9.7° C (50° F) with a maximum daily average of 19.1° C (66° F) and minimum of -2.1° C (28° F). Precipitation at the glacier has not been measured directly. Snowfall is the dominant form of precipitation and usually accumulates starting in September or October and continues through May or June. The nearest weather station with precipitation data is the Flattop SNOTEL located 25 km northeast of and 530 m lower than the Sperry station. Average yearly precipitation here from the years 1980-2010 was 1.70 m (67 in). Snowpack measurements made in June when the glacier is near peak accumulation reveal precipitation is likely much higher on the glacier. Values of 2.50 meters (98 in) of snow water equivalent to 3.00 m (118 in) are common. However the accumulation patterns on Sperry are not fully understood and it is unclear what percentage of these deep snow packs owe their existence to precipitation versus how much snow is transported onto the glacier by wind and avalanches.
Sources/Usage: Public Domain. View Media Details
Current data available from the Sperry weather station includes:
- Air Temperature
- Precipitation
- Relative Humidity
- Wind Speed
- Wind Direction
Hydrologic
At this time, stream discharge for Sperry Glacier is not measured. The glacier's broad expanse creates numerous discreet runoff streams which make gauging this glacier a challenge. Runoff data are not available for this glacier.
Previous Work
Sources/Usage: Public Domain. View Media Details
The glaciers of Glacier National Park have been the focus of visitor and scientific interest since before the park was established in 1910. Because it is relatively easy to access, Sperry Glacier has one of the most extensive records of historic data and measurement in the region. The earliest photo of the glacier dates back to 1894 and the earliest map was created in 1901. William Alden, a geologist for the USGS, explored the glacier and published the first scientific measurements and descriptions in the early 20th century (Alden, 1914; Alden, 1923). The glacier's retreat was documented by Dyson (1948) and the USGS and NPS conducted annual measurements of the glacier in the mid-20th century, including the installation of ablation stakes, measurements of flow speed and direction, and plane-table mapping that resulted in a detailed topographical map of the glacier with terminus locations from 1913-1969 (Johnson, 1980) (Reardon, et al, 2008). The progression of glacier retreat has been documented using satellite imagery and aerial photos (Key, et al., 2002), repeat photography, and annual GPS mapping of margins and terminus since 2003 by the USGS — CCME glacier monitoring program. Other parameters, such as depth measurement through the use of ice radar, GPS velocity measurements, and the determination of elevation profiles were included at the beginning of the monitoring program in 2005 in collaboration with Joel T. Harper of the University of Montana, Missoula.
Time-Series Data: GNP glacier margins
Little Ice Age glacier margins
USGS Glacier Retreat Factsheet
Regional Impacts
Sources/Usage: Public Domain. View Media Details
Sperry Glacier is a small alpine glacier located in Glacier National Park in the U.S. Rocky Mountains of Montana. It occupies a broad, shallow cirque along the Continental Divide which results in climatic influences from both maritime and continental air masses. Glaciers in this region have been decreasing in mass and extent during the 20th century in response to altered temperature and precipitation. Meltwater from these glaciers helps to regulate stream temperatures and maintains streamflow during late summer and drought periods when other sources are depleted. As glaciers disappear, summer stream temperatures will increase and may cause the local extinction of temperature sensitive aquatic insects, disrupting the basis of the aquatic food chain. Such changes in stream habitat may also have adverse effects for the threatened native bull trout and increase hybridization of native cutthroat trout, leaving the native population at risk. Loss of a sustained water source may impact vegetation communities and contribute to a dryer, more fire-prone landscape overall. Aside from these and other ecological consequences of losing glaciers, local economies and livelihoods are connected to glaciers in this region as well. Meltwater also contributes to agricultural practices and recreational uses like boating and fishing. Sperry, and the other remaining glaciers in Glacier National Park, also provide an aesthetic and historic component to the local tourism-based economy. The loss of glaciers in this region, and associated ecologic and socioeconomic contributions, are issues that scientists are exploring to assist land managers in determining adaptive strategies.
Selected Publications:
Clark, Adam M., Joel T. Harper, and Daniel B. Fagre, 2015, Glacier-Derived August Runoff in Northwest Montana. Arctic, Antarctic, and Alpine Research 47(1):1-16.
Federal Register, 2019, Threatened Species Status for Meltwater Lednian Stonefly and Western Glacier Stonefly
Hotaling, S, Clint C Muhlfeld, J Joseph Giersch, et al. 2018. Demographic modelling reveals a history of divergence with gene flow for a glacially tied stonefly in a changing post‐Pleistocene landscape. Journal of Biogeography 45: 304– 317, doi:10.1111/jbi.13125
Muhlfeld, Clint C, J. Joseph Giersch, F. Richard Hauer, Gregory T. Pederson, Gordon Luikart, Douglas P. Peterson, Christopher C. Downs, and Daniel B. Fagre, 2011, Climate change links fate of glaciers and an endemic alpine invertebrate. Climatic Change Letters. doi:10.1007/s10584-011-0057-1.
Pederson, G.T., L.J. Graumlich, D.B. Fagre, T. Kipfer and C.C. Muhlfeld, 2009, A century of climate and ecosystem change in Western Montana: what do temperature trends portend?. Climatic Change 96: doi:10.1007/s10584-009-9642-y, 22pp.
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...
South Cascade Glacier
South Cascade Glacier is located in the midlatitude maritime climate of the North Cascade Mountains of Washington State. Glacier observations began at this site in 1958.
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.
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.
Additional Research Glaciers
Black Rapids, Columbia and Hubbard glaciers are also researched by the USGS.
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.
Mass Balance Summary
The USGS Benchmark Glacier Project measures changes in mass balance at five benchmark glaciers: Gulkana (AK), Wolverine (AK), Lemon Creek (AK), South Cascade (WA), and Sperry (MT).
Mass Balance Methods - Measuring Glacier Change
Nearly all Earth's alpine glaciers are losing ice, usually expressed as loss of mass. Rates of mass loss for North American glaciers are among the highest on Earth (Gardner, 2013) and shrinking glaciers are often the most visible indicators of mountain ecosystems responding to climate change.
Scientist working on Sperry Glacier in Glacier National Park, Montana
Scientist working on Sperry Glacier in Glacier National Park, Montana. Sperry Glacier occupies a broad, shallow cirque situated just beneath and west of the Continental Divide in the Lewis Mountain Range of Glacier National Park, Montana. Due to its position on the Continental Divide the glacier is influenced by both maritime and continental air masses.
Researcher on Sperry Glacier
Researcher holds an ablation stake and winter snow probe during spring mass balance field work on Gulkana Glacier, AK.
Researcher holds an ablation stake and winter snow probe during spring mass balance field work on Gulkana Glacier, AK.
Researchers on Sperry Glacier
Researchers get organized to begin mass balance field work after skiing to Sperry Glacier.
Researchers get organized to begin mass balance field work after skiing to Sperry Glacier.
Sperry Glacier snow core
Snow core measurements help scientists determine snow density, which is used to determine the mass balance of Sperry Glacier.
Snow core measurements help scientists determine snow density, which is used to determine the mass balance of Sperry Glacier.
Measurement stakes are carried across Sperry Glacier in Glacier NP.
Measurement stakes are carried across Sperry Glacier in Glacier National Park, Montana, during spring mass balance field work in 2019.
Measurement stakes are carried across Sperry Glacier in Glacier National Park, Montana, during spring mass balance field work in 2019.
USGS personnel maintaining weather station on glacier
USGS personnel maintaining weather station on Sperry Glacier in Glacier National Park
USGS personnel maintaining weather station on Sperry Glacier in Glacier National Park
Researcher on Sperry Glacier
A researcher on Sperry Glacier navigates to the next mass balance survey location.
A researcher on Sperry Glacier navigates to the next mass balance survey location.
Scientists collecting snow core sample on Sperry Glacier in Glacier National Park, Montana
Scientists collecting snow core samples on Sperry Glacier in Glacier National Park, Montana.
Scientists collecting snow core samples on Sperry Glacier in Glacier National Park, Montana.
A hand-dug snow pit on Sperry Glacier
From a hand-dug snow pit, a researcher samples cores of surface snow at Sperry Glacier to determine snow density, a measure needed to calculate glacier mass balance.
From a hand-dug snow pit, a researcher samples cores of surface snow at Sperry Glacier to determine snow density, a measure needed to calculate glacier mass balance.
Aerial view of Sperry Glacier in Glacier National Park, Montana
Aerial view of Sperry Glacier in Glacier National Park, Montana. Sperry Glacier occupies a broad, shallow cirque situated just beneath and west of the Continental Divide in the Lewis Mountain Range of Glacier National Park, Montana. Due to its position on the Continental Divide the glacier is influenced by both maritime and continental air masses.
Aerial view of Sperry Glacier in Glacier National Park, Montana. Sperry Glacier occupies a broad, shallow cirque situated just beneath and west of the Continental Divide in the Lewis Mountain Range of Glacier National Park, Montana. Due to its position on the Continental Divide the glacier is influenced by both maritime and continental air masses.
Sperry Glacier is located along the Continental Divide within Glacier National Park, Montana. It represents the midlatitude continental or transitional climate. Glacier observations began at this site in 2005.
Return to Glaciers and Climate Project
Sources/Usage: Public Domain. View Media Details
Sperry Glacier occupies a broad, shallow cirque situated just beneath and west of the Continental Divide in the Lewis Mountain Range of Glacier National Park, Montana. This northeast facing glacier is wider than it is long relative to its flow direction and spans about 300 m in elevation with a median altitude of 2450 m. It ranks as a moderately sized glacier for this region, which contains the second highest concentration of glaciers in the U.S. Rocky Mountains. The glacier is in a ~4 km2 hanging cirque, and in 2014 it had an area of 0.80 km2, making Sperry Glacier the smallest of the benchmark glaciers.
Due to its position on the Continental Divide the glacier is influenced by both maritime and continental air masses. However, given its position on the western and predominantly windward side of the Continental Divide, Pacific storm systems dominate the weather. These bring heavy precipitation and moderate temperatures as warm, moist Pacific fronts collide with and lift over the Rocky Mountains. Temperature and precipitation patterns in northwest Montana are marked by strong altitudinal gradients. For valley sites at about 1000 m, mean temperatures for July, which is generally the warmest month of the year, are typically 15-17°C (59-63°F); they are roughly half that for mountain sites at 2500 m (Finklin, 1986). Annual precipitation averages 580 mm on the western and eastern edges of Glacier Park, but over 2500 mm at higher elevations in the Park's interior near the Continental Divide.
In 2005, the USGS Climate Change in Mountain Ecosystems (CCME) program established a glacier monitoring strategy in northwest Montana with the goal of assessing long-term changes to the region's glaciers. Through this monitoring program researchers also aimed to evaluate the hydrologic and ecologic effects of glaciers in Glacier National Park. Sperry Glacier was chosen as the benchmark study glacier due to its history of previous research, physical characteristics, and accessibility.
Research
Sources/Usage: Public Domain. View Media Details
Glacier mass balance
Sources/Usage: Public Domain. View Media Details
Sperry became the focus of extensive field research starting in 2005 as scientists employed standard glaciological methods (Ostrem and Brugman, 1991) to estimate glacier-wide seasonal and annual surface mass balances. Snow depths and densities are measured in the spring when the glacier's balance is at a maximum. Ablation stakes are also installed at this time and then checked periodically during the summer melt season with a final check in early autumn at the balance minima. With similar goals and methodologies, the Sperry Glacier mass balance project joined the established USGS Benchmark Program in 2013. The addition of Sperry to the long-established mass balance monitoring projects in Alaska and Washington will facilitate a broader understanding of glacier dynamics, hydrology, and glacier response to climate change.
Direct field measurements are combined with weather data and imagery analyses to calculate the seasonal and annual mass balance of each glacier. Access all the data here.
Meteorologic
In June 2006 the Sperry Glacier weather station (48° 37' 24.1932" N, 113° 45' 53.4347" W) was installed at an altitude of 2450 m on a rocky outcrop about 100 m from the western edge of the glacier. Sensors measured air temperature, wind speed and direction, incoming solar radiation, and relative humidity. It became apparent that the 2 m mast height was not sufficient as the station was buried every winter and typically did not melt out until June. In some years the sensors were damaged so severely by snowpack creep that they needed replacing. During years with exceptionally heavy snowfall, such as in 2011, the station did not melt out until late July. The station was abandoned in 2012 due to these issues and there are no data for that year. But in 2013, the station was re-installed and recorded data for most of the June through September ablation season. In September 2014 a new station was installed in the same location with a 4 m mast and fitted with new instruments including a net radiometer, a new power system, and satellite telemetry. The taller mast should keep the sensors above the snowpack surface during the winter allowing the station to remain operational year round.
There are complete records of daily average temperature for the months July and August 2006-2011 and 2013. Most of the ablation on the glacier occurs during these two summer months. For the period of record, the mean July-August daily average temperature was 9.7° C (50° F) with a maximum daily average of 19.1° C (66° F) and minimum of -2.1° C (28° F). Precipitation at the glacier has not been measured directly. Snowfall is the dominant form of precipitation and usually accumulates starting in September or October and continues through May or June. The nearest weather station with precipitation data is the Flattop SNOTEL located 25 km northeast of and 530 m lower than the Sperry station. Average yearly precipitation here from the years 1980-2010 was 1.70 m (67 in). Snowpack measurements made in June when the glacier is near peak accumulation reveal precipitation is likely much higher on the glacier. Values of 2.50 meters (98 in) of snow water equivalent to 3.00 m (118 in) are common. However the accumulation patterns on Sperry are not fully understood and it is unclear what percentage of these deep snow packs owe their existence to precipitation versus how much snow is transported onto the glacier by wind and avalanches.
Sources/Usage: Public Domain. View Media Details
Current data available from the Sperry weather station includes:
- Air Temperature
- Precipitation
- Relative Humidity
- Wind Speed
- Wind Direction
Hydrologic
At this time, stream discharge for Sperry Glacier is not measured. The glacier's broad expanse creates numerous discreet runoff streams which make gauging this glacier a challenge. Runoff data are not available for this glacier.
Previous Work
Sources/Usage: Public Domain. View Media Details
The glaciers of Glacier National Park have been the focus of visitor and scientific interest since before the park was established in 1910. Because it is relatively easy to access, Sperry Glacier has one of the most extensive records of historic data and measurement in the region. The earliest photo of the glacier dates back to 1894 and the earliest map was created in 1901. William Alden, a geologist for the USGS, explored the glacier and published the first scientific measurements and descriptions in the early 20th century (Alden, 1914; Alden, 1923). The glacier's retreat was documented by Dyson (1948) and the USGS and NPS conducted annual measurements of the glacier in the mid-20th century, including the installation of ablation stakes, measurements of flow speed and direction, and plane-table mapping that resulted in a detailed topographical map of the glacier with terminus locations from 1913-1969 (Johnson, 1980) (Reardon, et al, 2008). The progression of glacier retreat has been documented using satellite imagery and aerial photos (Key, et al., 2002), repeat photography, and annual GPS mapping of margins and terminus since 2003 by the USGS — CCME glacier monitoring program. Other parameters, such as depth measurement through the use of ice radar, GPS velocity measurements, and the determination of elevation profiles were included at the beginning of the monitoring program in 2005 in collaboration with Joel T. Harper of the University of Montana, Missoula.
Time-Series Data: GNP glacier margins
Little Ice Age glacier margins
USGS Glacier Retreat Factsheet
Regional Impacts
Sources/Usage: Public Domain. View Media Details
Sperry Glacier is a small alpine glacier located in Glacier National Park in the U.S. Rocky Mountains of Montana. It occupies a broad, shallow cirque along the Continental Divide which results in climatic influences from both maritime and continental air masses. Glaciers in this region have been decreasing in mass and extent during the 20th century in response to altered temperature and precipitation. Meltwater from these glaciers helps to regulate stream temperatures and maintains streamflow during late summer and drought periods when other sources are depleted. As glaciers disappear, summer stream temperatures will increase and may cause the local extinction of temperature sensitive aquatic insects, disrupting the basis of the aquatic food chain. Such changes in stream habitat may also have adverse effects for the threatened native bull trout and increase hybridization of native cutthroat trout, leaving the native population at risk. Loss of a sustained water source may impact vegetation communities and contribute to a dryer, more fire-prone landscape overall. Aside from these and other ecological consequences of losing glaciers, local economies and livelihoods are connected to glaciers in this region as well. Meltwater also contributes to agricultural practices and recreational uses like boating and fishing. Sperry, and the other remaining glaciers in Glacier National Park, also provide an aesthetic and historic component to the local tourism-based economy. The loss of glaciers in this region, and associated ecologic and socioeconomic contributions, are issues that scientists are exploring to assist land managers in determining adaptive strategies.
Selected Publications:
Clark, Adam M., Joel T. Harper, and Daniel B. Fagre, 2015, Glacier-Derived August Runoff in Northwest Montana. Arctic, Antarctic, and Alpine Research 47(1):1-16.
Federal Register, 2019, Threatened Species Status for Meltwater Lednian Stonefly and Western Glacier Stonefly
Hotaling, S, Clint C Muhlfeld, J Joseph Giersch, et al. 2018. Demographic modelling reveals a history of divergence with gene flow for a glacially tied stonefly in a changing post‐Pleistocene landscape. Journal of Biogeography 45: 304– 317, doi:10.1111/jbi.13125
Muhlfeld, Clint C, J. Joseph Giersch, F. Richard Hauer, Gregory T. Pederson, Gordon Luikart, Douglas P. Peterson, Christopher C. Downs, and Daniel B. Fagre, 2011, Climate change links fate of glaciers and an endemic alpine invertebrate. Climatic Change Letters. doi:10.1007/s10584-011-0057-1.
Pederson, G.T., L.J. Graumlich, D.B. Fagre, T. Kipfer and C.C. Muhlfeld, 2009, A century of climate and ecosystem change in Western Montana: what do temperature trends portend?. Climatic Change 96: doi:10.1007/s10584-009-9642-y, 22pp.
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...
South Cascade Glacier
South Cascade Glacier is located in the midlatitude maritime climate of the North Cascade Mountains of Washington State. Glacier observations began at this site in 1958.
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.
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.
Additional Research Glaciers
Black Rapids, Columbia and Hubbard glaciers are also researched by the USGS.
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.
Mass Balance Summary
The USGS Benchmark Glacier Project measures changes in mass balance at five benchmark glaciers: Gulkana (AK), Wolverine (AK), Lemon Creek (AK), South Cascade (WA), and Sperry (MT).
Mass Balance Methods - Measuring Glacier Change
Nearly all Earth's alpine glaciers are losing ice, usually expressed as loss of mass. Rates of mass loss for North American glaciers are among the highest on Earth (Gardner, 2013) and shrinking glaciers are often the most visible indicators of mountain ecosystems responding to climate change.
Scientist working on Sperry Glacier in Glacier National Park, Montana
Scientist working on Sperry Glacier in Glacier National Park, Montana. Sperry Glacier occupies a broad, shallow cirque situated just beneath and west of the Continental Divide in the Lewis Mountain Range of Glacier National Park, Montana. Due to its position on the Continental Divide the glacier is influenced by both maritime and continental air masses.
Scientist working on Sperry Glacier in Glacier National Park, Montana. Sperry Glacier occupies a broad, shallow cirque situated just beneath and west of the Continental Divide in the Lewis Mountain Range of Glacier National Park, Montana. Due to its position on the Continental Divide the glacier is influenced by both maritime and continental air masses.
Researcher on Sperry Glacier
Researcher holds an ablation stake and winter snow probe during spring mass balance field work on Gulkana Glacier, AK.
Researcher holds an ablation stake and winter snow probe during spring mass balance field work on Gulkana Glacier, AK.
Researchers on Sperry Glacier
Researchers get organized to begin mass balance field work after skiing to Sperry Glacier.
Researchers get organized to begin mass balance field work after skiing to Sperry Glacier.
Sperry Glacier snow core
Snow core measurements help scientists determine snow density, which is used to determine the mass balance of Sperry Glacier.
Snow core measurements help scientists determine snow density, which is used to determine the mass balance of Sperry Glacier.
Measurement stakes are carried across Sperry Glacier in Glacier NP.
Measurement stakes are carried across Sperry Glacier in Glacier National Park, Montana, during spring mass balance field work in 2019.
Measurement stakes are carried across Sperry Glacier in Glacier National Park, Montana, during spring mass balance field work in 2019.
USGS personnel maintaining weather station on glacier
USGS personnel maintaining weather station on Sperry Glacier in Glacier National Park
USGS personnel maintaining weather station on Sperry Glacier in Glacier National Park
Researcher on Sperry Glacier
A researcher on Sperry Glacier navigates to the next mass balance survey location.
A researcher on Sperry Glacier navigates to the next mass balance survey location.
Scientists collecting snow core sample on Sperry Glacier in Glacier National Park, Montana
Scientists collecting snow core samples on Sperry Glacier in Glacier National Park, Montana.
Scientists collecting snow core samples on Sperry Glacier in Glacier National Park, Montana.
A hand-dug snow pit on Sperry Glacier
From a hand-dug snow pit, a researcher samples cores of surface snow at Sperry Glacier to determine snow density, a measure needed to calculate glacier mass balance.
From a hand-dug snow pit, a researcher samples cores of surface snow at Sperry Glacier to determine snow density, a measure needed to calculate glacier mass balance.
Aerial view of Sperry Glacier in Glacier National Park, Montana
Aerial view of Sperry Glacier in Glacier National Park, Montana. Sperry Glacier occupies a broad, shallow cirque situated just beneath and west of the Continental Divide in the Lewis Mountain Range of Glacier National Park, Montana. Due to its position on the Continental Divide the glacier is influenced by both maritime and continental air masses.
Aerial view of Sperry Glacier in Glacier National Park, Montana. Sperry Glacier occupies a broad, shallow cirque situated just beneath and west of the Continental Divide in the Lewis Mountain Range of Glacier National Park, Montana. Due to its position on the Continental Divide the glacier is influenced by both maritime and continental air masses.