Lemon Creek Glacier is located at the southernmost tip of the Juneau Icefield in Southeast Alaska, USA, approximately 6.5 km northeast of the city of Juneau.
2025 USGS Benchmark Glaciers Executive Summary
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By Ecosystems Land Change Science Program
March 11, 2026
2025 Data Now Available: Explore how the USGS Benchmark Glaciers have changed in 2025
Return to Glaciers and Landscape Change
Explore the USGS Benchmark Glaciers mass balance methods for measuring glacier change
2025 Benchmark Glacier Results
Benchmark Glaciers in Alaska had variable (and modest) mass gains and losses (Fig. 1).
- Wolverine Glacier gained mass in 2025, the first time since 2012.
- Gulkana and Lemon Creek Glaciers lost mass for the 17th and 13th consecutive years, respectively.
Benchmark Glaciers in the contiguous states had record and near record mass losses
- Glacier mass loss at South Cascade Glacier (Washington) was the highest on record.
- Mass loss at Sperry Glacier (Montana) was the second highest on record.
Overall, 2025 was characterized by glacier mass loss driven primarily by warm summer conditions, with Wolverine Glacier as a notable exception.
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Media
Sources/Usage: Public Domain. View Media Details
How did 2025 annual mass balances compare to previous years?
In Alaska, Gulkana and Lemon Creek glaciers experienced moderate mass loss, marking their 17th and 13th consecutive years of negative annual mass balance, respectively. Conversely, Wolverine Glacier experienced moderate mass gain — its first positive annual mass balance since 2012, ending a 12-year streak of negative balances. In the contiguous United States, Sperry Glacier in Glacier National Park, MT saw its second highest mass loss year since measurements began in 2005. South Cascade Glacier in the Cascade Mountains of Washington underwent the greatest mass loss year since measurements began in 1958 (Fig. 2.).
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How did winter snowfall contribute to each glacier's mass balance?
At Wolverine Glacier, winter precipitation exceeded normal levels beginning in November and remained above average throughout the remainder of the 2024 – 25 accumulation season. Lemon Creek Glacier experienced near-normal winter precipitation through the accumulation season. At Sperry Glacier, precipitation began accumulating approximately one month later than normal. Gulkana, Sperry, and South Cascade glaciers all ended the 2024 – 25 accumulation season with below-average winter precipitation (Fig. 3.).
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How did summer temperatures contribute to each glacier's mass balance?
All three Alaska glaciers experienced cooler than average temperatures during the first half of summer, limiting melt. Wolverine and Gulkana Glaciers had a delayed start to the ablation season. At Wolverine Glacier remained cooler than average through the end of summer, contributing to its positive mass balance. Gulkana and Lemon Creek glaciers ended the summer moderately warmer than average, offsetting some of the effects of the cool early season. In the contiguous United States, both Sperry and South Cascade glaciers experienced significantly warmer than average temperatures throughout the summer, driving the exceptional mass loss observed at both sites (Fig. 4.).
Explore the USGS Benchmark Glaciers in context of global glacier studies
Glaciers and Landscape Change
Mountain glaciers are dynamic reservoirs of frozen water, deeply interconnected with their surrounding ecosystems. Glacier change in North America has major societal impacts, including to water resources, natural hazard risk, tourism disruption, fisheries, and global sea level change. Understanding and quantifying precise connections between changing glaciers, the surrounding landscape and climate...
Aerial photographs of South Cascade Glacier represent 57 years of change
Aerial photograph of South Cascade Glacier, WA taken August 13th, 1958 (before image) and October 14th, 2015 (after image).
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Lemon Creek Glacier
Lemon Creek Glacier is located at the southernmost tip of the Juneau Icefield in Southeast Alaska, USA, approximately 6.5 km northeast of the city of Juneau.
Collecting data at an ablation stake on Wolverine Glacier
Collecting data at an ablation stake on Wolverine GlacierUSGS scientist, Chris McNeil, collects data at an ablation stake on Wolverine Glacier near the end of the glacial melt season.
Collecting data at an ablation stake on Wolverine Glacier
Collecting data at an ablation stake on Wolverine GlacierUSGS scientist, Chris McNeil, collects data at an ablation stake on Wolverine Glacier near the end of the glacial melt season.
Crevassed terminus of Gulkana Glacier
Heavily crevassed terminus of Gulkana Glacier, AK, near the end of the 2016 ablation (melt) season.
Heavily crevassed terminus of Gulkana Glacier, AK, near the end of the 2016 ablation (melt) season.
Gulkana Glacier
Heavily crevassed glacial ice flows across scoured rock in late summer at Gulkana Glacier, AK.
Heavily crevassed glacial ice flows across scoured rock in late summer at Gulkana Glacier, AK.
Gulkana Glacier
Gulkana Glacier is located along the south flank of the eastern Alaska Range.
Gulkana Glacier is located along the south flank of the eastern Alaska Range.
Aerial photo of Sperry Glacier
Aerial photo of Sperry Glacier, Digital Globe image taken 08/26/2016. Aerial imagery, like this photo of Sperry Glacier, is used to create digital elevation models (DEMs) used to extrapolate mass balance field measurements over the entire glacier.
Aerial photo of Sperry Glacier, Digital Globe image taken 08/26/2016. Aerial imagery, like this photo of Sperry Glacier, is used to create digital elevation models (DEMs) used to extrapolate mass balance field measurements over the entire glacier.
A scientist dumps DNA tracer into a moulin on Wolverine Glacier
A scientist dumps DNA tracer into a moulin on Wolverine GlacierA scientist dumps DNA tracer into a moulin on Wolverine Glacier to assess water flow through the glacier as part of research aimed at understanding glacier processes.
A scientist dumps DNA tracer into a moulin on Wolverine Glacier
A scientist dumps DNA tracer into a moulin on Wolverine GlacierA scientist dumps DNA tracer into a moulin on Wolverine Glacier to assess water flow through the glacier as part of research aimed at understanding glacier processes.
Sperry Glacier Panorama 2008 in black and white.
Sperry Glacier Panorama 2008 in black and white.
Sperry Glacier Mid View 2008 in black and white.
Sperry Glacier Mid View 2008 in black and white.
Sperry Glacier Mid View 2008 in color.
Sperry Glacier Mid View 2008 in color.
Sperry Glacier Mid View c1930.
Sperry Glacier Mid View circa 1930. Images that were acquired from the University of Montana may be protected by copyright.
Sperry Glacier Mid View circa 1930. Images that were acquired from the University of Montana may be protected by copyright.
Sperry Glacier Panorama 1913.
Sperry Glacier Panorama 1913.
Sperry Glacier NE 2007 in color.
Sperry Glacier NE 2007 in color.
Sperry Glacier NE 2007 in black and white.
Sperry Glacier NE 2007 in black and white.
Sperry Glacier NE 1913.
Sperry Glacier NE 1913.
South Cascade Glacier October 14th, 2015
Aerial photograph of South Cascade Glacier, WA taken October 14th, 2015.
Aerial photograph of South Cascade Glacier, WA taken October 14th, 2015.
South Cascade Glacier, northwestern Washington State
South Cascade Glacier, northwestern Washington StateSouth Cascade Glacier, northwestern Washington State. South Cascade Glacier located in a north-northwest facing valley near the crest of the Cascade Range in northwest Washington state. In 1959 scientists with the USGS began collecting mass balance data on South Cascade Glacier, now one of five "benchmark glaciers" in the US.
South Cascade Glacier, northwestern Washington State
South Cascade Glacier, northwestern Washington StateSouth Cascade Glacier, northwestern Washington State. South Cascade Glacier located in a north-northwest facing valley near the crest of the Cascade Range in northwest Washington state. In 1959 scientists with the USGS began collecting mass balance data on South Cascade Glacier, now one of five "benchmark glaciers" in the US.
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.
Sperry Glacier, Sept. 25, 2015
This is an image taken in 2015 of Sperry Glacier in Glacier National Park. Accoriding to data released by the USGS, the warming climate has dramatically reduced the size of 39 glaciers in Montana since 1966, some by as much as 85 percent.
This is an image taken in 2015 of Sperry Glacier in Glacier National Park. Accoriding to data released by the USGS, the warming climate has dramatically reduced the size of 39 glaciers in Montana since 1966, some by as much as 85 percent.
Wolverine glacier weather station, Alaska
Wolverine weather station collects weather data near the glacier to aid mass balance. Wolverine Glacier is in the Kenai Mountains on the coast of south-central Alaska. In 1966 scientists with the USGS began making direct measurements of surface mass balance at Wolverine Glacier, one of the "benchmark glaciers" in Alaska.
Wolverine weather station collects weather data near the glacier to aid mass balance. Wolverine Glacier is in the Kenai Mountains on the coast of south-central Alaska. In 1966 scientists with the USGS began making direct measurements of surface mass balance at Wolverine Glacier, one of the "benchmark glaciers" in Alaska.
Scientists collecting snow core sample on Sperry Glacier in Glacier National Park, Montana
Scientists collecting snow core sample on Sperry Glacier in Glacier National Park, MontanaScientists collecting snow core samples on Sperry Glacier in Glacier National Park, Montana.
Scientists collecting snow core sample on Sperry Glacier in Glacier National Park, Montana
Scientists collecting snow core sample on Sperry Glacier in Glacier National Park, MontanaScientists collecting snow core samples on Sperry Glacier in Glacier National Park, Montana.
2025 Data Now Available: Explore how the USGS Benchmark Glaciers have changed in 2025
Return to Glaciers and Landscape Change
Explore the USGS Benchmark Glaciers mass balance methods for measuring glacier change
2025 Benchmark Glacier Results
Benchmark Glaciers in Alaska had variable (and modest) mass gains and losses (Fig. 1).
- Wolverine Glacier gained mass in 2025, the first time since 2012.
- Gulkana and Lemon Creek Glaciers lost mass for the 17th and 13th consecutive years, respectively.
Benchmark Glaciers in the contiguous states had record and near record mass losses
- Glacier mass loss at South Cascade Glacier (Washington) was the highest on record.
- Mass loss at Sperry Glacier (Montana) was the second highest on record.
Overall, 2025 was characterized by glacier mass loss driven primarily by warm summer conditions, with Wolverine Glacier as a notable exception.
Media
Sources/Usage: Public Domain. View Media Details
Media
Sources/Usage: Public Domain. View Media Details
How did 2025 annual mass balances compare to previous years?
In Alaska, Gulkana and Lemon Creek glaciers experienced moderate mass loss, marking their 17th and 13th consecutive years of negative annual mass balance, respectively. Conversely, Wolverine Glacier experienced moderate mass gain — its first positive annual mass balance since 2012, ending a 12-year streak of negative balances. In the contiguous United States, Sperry Glacier in Glacier National Park, MT saw its second highest mass loss year since measurements began in 2005. South Cascade Glacier in the Cascade Mountains of Washington underwent the greatest mass loss year since measurements began in 1958 (Fig. 2.).
Media
Sources/Usage: Public Domain. View Media Details
How did winter snowfall contribute to each glacier's mass balance?
At Wolverine Glacier, winter precipitation exceeded normal levels beginning in November and remained above average throughout the remainder of the 2024 – 25 accumulation season. Lemon Creek Glacier experienced near-normal winter precipitation through the accumulation season. At Sperry Glacier, precipitation began accumulating approximately one month later than normal. Gulkana, Sperry, and South Cascade glaciers all ended the 2024 – 25 accumulation season with below-average winter precipitation (Fig. 3.).
Media
Sources/Usage: Public Domain. View Media Details
How did summer temperatures contribute to each glacier's mass balance?
All three Alaska glaciers experienced cooler than average temperatures during the first half of summer, limiting melt. Wolverine and Gulkana Glaciers had a delayed start to the ablation season. At Wolverine Glacier remained cooler than average through the end of summer, contributing to its positive mass balance. Gulkana and Lemon Creek glaciers ended the summer moderately warmer than average, offsetting some of the effects of the cool early season. In the contiguous United States, both Sperry and South Cascade glaciers experienced significantly warmer than average temperatures throughout the summer, driving the exceptional mass loss observed at both sites (Fig. 4.).
Explore the USGS Benchmark Glaciers in context of global glacier studies
Glaciers and Landscape Change
Mountain glaciers are dynamic reservoirs of frozen water, deeply interconnected with their surrounding ecosystems. Glacier change in North America has major societal impacts, including to water resources, natural hazard risk, tourism disruption, fisheries, and global sea level change. Understanding and quantifying precise connections between changing glaciers, the surrounding landscape and climate...
Aerial photographs of South Cascade Glacier represent 57 years of change
Aerial photograph of South Cascade Glacier, WA taken August 13th, 1958 (before image) and October 14th, 2015 (after image).
Filter Total Items: 77
Lemon Creek Glacier
Lemon Creek Glacier is located at the southernmost tip of the Juneau Icefield in Southeast Alaska, USA, approximately 6.5 km northeast of the city of Juneau.
Lemon Creek Glacier is located at the southernmost tip of the Juneau Icefield in Southeast Alaska, USA, approximately 6.5 km northeast of the city of Juneau.
Collecting data at an ablation stake on Wolverine Glacier
Collecting data at an ablation stake on Wolverine GlacierUSGS scientist, Chris McNeil, collects data at an ablation stake on Wolverine Glacier near the end of the glacial melt season.
Collecting data at an ablation stake on Wolverine Glacier
Collecting data at an ablation stake on Wolverine GlacierUSGS scientist, Chris McNeil, collects data at an ablation stake on Wolverine Glacier near the end of the glacial melt season.
Crevassed terminus of Gulkana Glacier
Heavily crevassed terminus of Gulkana Glacier, AK, near the end of the 2016 ablation (melt) season.
Heavily crevassed terminus of Gulkana Glacier, AK, near the end of the 2016 ablation (melt) season.
Gulkana Glacier
Heavily crevassed glacial ice flows across scoured rock in late summer at Gulkana Glacier, AK.
Heavily crevassed glacial ice flows across scoured rock in late summer at Gulkana Glacier, AK.
Gulkana Glacier
Gulkana Glacier is located along the south flank of the eastern Alaska Range.
Gulkana Glacier is located along the south flank of the eastern Alaska Range.
Aerial photo of Sperry Glacier
Aerial photo of Sperry Glacier, Digital Globe image taken 08/26/2016. Aerial imagery, like this photo of Sperry Glacier, is used to create digital elevation models (DEMs) used to extrapolate mass balance field measurements over the entire glacier.
Aerial photo of Sperry Glacier, Digital Globe image taken 08/26/2016. Aerial imagery, like this photo of Sperry Glacier, is used to create digital elevation models (DEMs) used to extrapolate mass balance field measurements over the entire glacier.
A scientist dumps DNA tracer into a moulin on Wolverine Glacier
A scientist dumps DNA tracer into a moulin on Wolverine GlacierA scientist dumps DNA tracer into a moulin on Wolverine Glacier to assess water flow through the glacier as part of research aimed at understanding glacier processes.
A scientist dumps DNA tracer into a moulin on Wolverine Glacier
A scientist dumps DNA tracer into a moulin on Wolverine GlacierA scientist dumps DNA tracer into a moulin on Wolverine Glacier to assess water flow through the glacier as part of research aimed at understanding glacier processes.
Sperry Glacier Panorama 2008 in black and white.
Sperry Glacier Panorama 2008 in black and white.
Sperry Glacier Mid View 2008 in black and white.
Sperry Glacier Mid View 2008 in black and white.
Sperry Glacier Mid View 2008 in color.
Sperry Glacier Mid View 2008 in color.
Sperry Glacier Mid View c1930.
Sperry Glacier Mid View circa 1930. Images that were acquired from the University of Montana may be protected by copyright.
Sperry Glacier Mid View circa 1930. Images that were acquired from the University of Montana may be protected by copyright.
Sperry Glacier Panorama 1913.
Sperry Glacier Panorama 1913.
Sperry Glacier NE 2007 in color.
Sperry Glacier NE 2007 in color.
Sperry Glacier NE 2007 in black and white.
Sperry Glacier NE 2007 in black and white.
Sperry Glacier NE 1913.
Sperry Glacier NE 1913.
South Cascade Glacier October 14th, 2015
Aerial photograph of South Cascade Glacier, WA taken October 14th, 2015.
Aerial photograph of South Cascade Glacier, WA taken October 14th, 2015.
South Cascade Glacier, northwestern Washington State
South Cascade Glacier, northwestern Washington StateSouth Cascade Glacier, northwestern Washington State. South Cascade Glacier located in a north-northwest facing valley near the crest of the Cascade Range in northwest Washington state. In 1959 scientists with the USGS began collecting mass balance data on South Cascade Glacier, now one of five "benchmark glaciers" in the US.
South Cascade Glacier, northwestern Washington State
South Cascade Glacier, northwestern Washington StateSouth Cascade Glacier, northwestern Washington State. South Cascade Glacier located in a north-northwest facing valley near the crest of the Cascade Range in northwest Washington state. In 1959 scientists with the USGS began collecting mass balance data on South Cascade Glacier, now one of five "benchmark glaciers" in the US.
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.
Sperry Glacier, Sept. 25, 2015
This is an image taken in 2015 of Sperry Glacier in Glacier National Park. Accoriding to data released by the USGS, the warming climate has dramatically reduced the size of 39 glaciers in Montana since 1966, some by as much as 85 percent.
This is an image taken in 2015 of Sperry Glacier in Glacier National Park. Accoriding to data released by the USGS, the warming climate has dramatically reduced the size of 39 glaciers in Montana since 1966, some by as much as 85 percent.
Wolverine glacier weather station, Alaska
Wolverine weather station collects weather data near the glacier to aid mass balance. Wolverine Glacier is in the Kenai Mountains on the coast of south-central Alaska. In 1966 scientists with the USGS began making direct measurements of surface mass balance at Wolverine Glacier, one of the "benchmark glaciers" in Alaska.
Wolverine weather station collects weather data near the glacier to aid mass balance. Wolverine Glacier is in the Kenai Mountains on the coast of south-central Alaska. In 1966 scientists with the USGS began making direct measurements of surface mass balance at Wolverine Glacier, one of the "benchmark glaciers" in Alaska.
Scientists collecting snow core sample on Sperry Glacier in Glacier National Park, Montana
Scientists collecting snow core sample on Sperry Glacier in Glacier National Park, MontanaScientists collecting snow core samples on Sperry Glacier in Glacier National Park, Montana.
Scientists collecting snow core sample on Sperry Glacier in Glacier National Park, Montana
Scientists collecting snow core sample on Sperry Glacier in Glacier National Park, MontanaScientists collecting snow core samples on Sperry Glacier in Glacier National Park, Montana.