2025 North Cascade Glacier Climate Project Field Plan-42nd Year.

On By mspeltoIn North Cascade Glaciers

2025 Field Season: For the 42nd consecutive summer we are heading into the field to measure and communicate the impact of climate change on North Cascade glaciers. This year an overall focus of the project is supporting the UN’s “International Year for Glaciers’ Preservation”. This means focusing on glaciers that have disappeared and are in critical danger of disappearing in the next decade. Jill Pelto, Art Director and Mauri Pelto, Science Director

This field season follows the 2021-2024 seasons that featured either historic heat waves and/or periods of extended warm weather. The heat led to a greater exposure of bare ice on glaciers with a higher albedo and greater density. The observed melt rates are 7-9 cm/day water equivalent during warm weather events vs 4-6 for snow surfaces. This led to substantial mass losses on North Cascade glacier for the four years of over ~6 m. 

Science objectives: We will complete detailed measurements on 10 glaciers, three of which are part of the World Glacier Monitoring Service reference glacier network (48 glaciers globally), which have 30+ consecutive years of mass balance observations. This summer we will have an opportunity to assess the long-term ramifications of the 2013-2024 period of unprecedented mass balance losses and associated glacier changes, with detailed mass balance, crevasse depths and glacier surface elevation profiling.  We also focus on the impact of diminishing glacier size on downstream runoff.

Drilling and emplacing ablation stakes on Sholes Glacier.

Art Objectives: We will collaborate with several artists who will join us for a portion of the field season. They will be able to create their own work about the landscape and the science or may join us for fieldwork and make plans for future artwork. We hope to use this art to share our research with a broader audience and highlight the beauty and importance of these places. 

Cal Waichler Sketch of Lower Curtis Glacier.

Communication Objectives: We will leverage the brands of our expedition sponsors and the focus on vanishing glaciers that the UN brings this year. These organizations can help spread our message. We will utilize a combination of artists and scientists to tell the story.

From the Glaciers to the Sea: this is one of two paintings that tells stories of watersheds fed by North Cascade glaciers that flow out into the Puget Sound. The snowpack and glaciers in the mountains in this region provide crucial meltwater to river systems, many of which connect critically to the ocean.

Field Team 2025:

Jill Pelto (she/her) is an artist and scientist from New England who grew up loving winter sports and trips to the mountains. She incorporates scientific research and data into paintings and prints to communicate environmental changes. Her multi-disciplinary work weaves visual narratives that reveal the reality of human impacts on this planet. She completed both her B.A. degrees in Studio Art and Earth and Climate Science, and her M.S. focused on studying the stability of the Antarctic Ice Sheet at the University of Maine, spending two field seasons at a remote camp in the southern Transantarctic Mountains. Jill will be joining the project for her 15th field season. She is excited about continuing to document the change in North Cascade glaciers that she has witnessed each of the last ten years — through science and art.

Jill’s 2025 Paintings inspired by our work about the Skykomish River Watershed and the Nooksack River Watershed.

Mauri Pelto (he/him) has directed the project since its founding in 1984, spending more than 800 nights camped out adjacent to these glaciers. He is the United States representative to the World Glacier Monitoring Service. For 15 years he has been author of the blog “From a Glacier’s Perspective”, and associate editor for three science journals.  He is on the Science Advisory Board for NASA’s Earth Observatory. His primary position is Associate Provost at Nichols College, where he has been a professor since 1989. He either runs on trails or skis on alpine and cross country trails every day.

Emmett Elsom (he/him) is an environmental science student at Western Washington University from Portland, Oregon. Growing up mountaineering and backpacking in the Cascade Range, he developed a love for the region and a fascination with the complexities of its ecosystems. In 2024 he had an opportunity to work In the field with the Oregon Glaciers Institute, assisting with SNOTEL data collection and fieldwork. This year, he is looking forward to broadening his understanding of the ecological role of glaciers and their melt across the Pacific Northwest, and the power of utilizing art in science. 

Caitlin Quirk (she/her) is a Masters student of Environmental Humanities at the University of Utah. She writes essays and poetry about socio-environmental justice, land relations, and political ecologies of climate change. Before graduate school, Caitlin worked as a mountaineering instructor and environmental researcher. Through these roles, she formed deep relationships with glaciers throughout the Pacific Northwest.  

Katie Hovind (she/her) is an environmental science student at Western Washington University. She feels a deep connection to the Cascade mountains and their watersheds from growing up in this region, and hopes to share their beauty and importance with others. She was a field assistant with NCGCP last year, and is excited to continue collaborating this year to explore ways science and art can evoke caring—for protection of natural spaces and response to the climate crisis. This season, she will help conduct a vegetational succession study at the Easton’s terminus to observe the changing alpine plant growth in the wake of a receding glacier.

Margaret Kingston: is an oil painter and art educator from Winthrop, Washington. Originally from New Hampshire, she moved 3000 miles with her husband Jonathan Baker to the Methow Valley after visiting the North Cascades National Park. Landscapes of the Pacific Northwest have been her inspiration for the past 13 years, captured first through a photo then realistically painted on canvas. As a backcountry skier, hiker, and biker she captures the energy of places these activities take you. With funding from the Mary Kiesau Fellowship Grant, Margaret will plein air paint on site in honor of her friend Mary Kiesau. Her observations during time spent with the North Cascade Glacier Climate Project will be shared through the resulting artwork and at a community event in the Methow Valley. Learn more about Margaret Kingston’s work at MkOilPaintings.com 

Claire Sianna Seaman (she/her) is a painter, filmmaker, and printmaker from Leavenworth, WA. She holds a BA from Smith College in Studio Art, with a concentration in Climate Change. She is currently earning her MA in Human Geography at the University of British Columbia. Claire has been featured in the Wild and Scenic Film Festival Art Exhibition and received an Artist Trust GAP Award. She worked with scientists from the University of Washington Climate Impacts Group  to create an art piece that imagined climate resiliency in the Pacific Northwest. This piece is currently part of the 5th National Climate Assessment Art x Climate Gallery on display at the Smithsonian Natural History Museum in Washington, D.C https://www.clairesianna.com/

2025 Schedule 

July 28:   Hike In Columbia. 

July 29:   Columbia Glacier survey

July 30:   Hike Out Columbia/Hike in Lower Curtis

July 31:   Lower Curtis Glacier Survey

Aug. 1:    Hike out, Hike in Ptarmigan Ridge

Aug. 2:    Sholes Glacier

Aug. 3:    Rainbow Glacier

Aug. 4:    Rainbow Glacier

Aug. 5:    Hike out. Hike in Easton Glacier (Resupply in Bellingham WA) 

Aug. 6:    Easton Glacier

Aug. 7:    Deming Glacier

Aug. 8:    Easton Glacier

Aug. 9:    Easton Glacier

Aug. 10:  Hike in Mount Daniels

Aug. 11:  Mount Daniels Survey

Aug. 12:  Ice Worm Glacier Survey-Exit

Assessing Crevasse Depth on Easton Glacier

Ptarmigan Ridge-Shuksan Arm Developing Landscape of Glacier Loss

On By mspeltoIn glacier climate change, Glacier Observations, North Cascade Glaciers

Glaciers on the ridge from Moutn Shuksan to Mount Baker that we observed to be active in mid 1980s, identified in GLIMS map below. Above Sentinel image from 9-9-2023. Glaciers that are no longer glaciers in yellow, seven of them including Mount Ann=MA, Shuksan Arm=SA, Coleman Pinnacle East/West=CPW/CPE, Camp Kiser=CK, Table Mountain=TM and HBB=Happy Bunny Butte. We still monitor each year Lower Curtis, Rainbow and Sholes.

The two most prominent mountains of the North Cascades Mount Shuksan and Mount Baker are connected by a ridge from Shuksan Arm to Ptarmigan Ridge. We visited 12 glaciers along and close to this ridge in the mid-1980s, to decide which to monitor annually. At that time each of these had active crevasses and significant area of glacier ice. We By the end of 2023 seven of the twelve glaciers are gone. We continue to monitor Lower Curtis, Rainbow and Sholes Glacier in detail. Portals and Ptarmigan Ridge Glacier which we visit every year, but do not assess in detail, will likely disappear in the next few years. Below is the evolving area and the date the glacier was lost, the area reported in the 1958/84 period and 2015 are from GLIMS and the 2023 area we determined from Sentinel imagery.

GlacierGLIMS IDYear Lost1958/84 Area2015 Area2023 Area
Camp KiserG238275E48809N19930.220.030
Happy Bunny ButteG238277E48834N20050.16600
Table MountainG238295E48850N20150.15800.008
Coleman PinnacleG238269E48826N20180.560.0310.018
Mount AnnG238341E48818N20220.120.070.01
Shuksan ArmG238362E48838N20230.160.070.03

1963 image of Ptarmigan Ridge sent to me by Austin Post.

Ptarmigan Ridge glaciers in 1993-all small but still all nearly joined.

In 2024 the lack of glacier ice or perennial snow along Ptarmigan Ridge is evident.

Novatak Glacier, Alaska Rifting in 2025 Reveals Forthcoming Rapid Lake Development in 2025

On By mspeltoIn alaska glacier retreat, Glacier Observations1 Comment
A network of extensive rifts have developed since 2023, yellow arrows. The fringing proglacial lake has not expanded. Rifting indicates uplift from partially floating glacier area.

Ice flow in the region around the developing lake, which is near the boundary with Yakutat Glacier in Sentinel Image from June 20, 2025

Novatak Glacier is between the Yakutat and East Novatak Glacier in southeast Alaska. The glacier retreated 1 km from 1987-2023 (NASA EO, 2015). The majority of the accumulation zone of these three glaciers is below 1000 m, which has made them particularly vulnerable to the warming climate. The result has been expansion of the proglacial lake, Harlequin Lake, at Yakutat Glacier from 1984 to 2024 from 50 km2 to 108 km2 (Pelto & NASA EO, 2024). There was no lake in 1908.

Novatak Glacier has been slow to form a substantial terminus lake unlike its neighbors, possibly because it lacks a sufficient basin. This has limited the retreat of this glacier as it thins. The developing rifts does show a large lake will form, with an area of 10-12 km2 . This will isolate the terminus from the main inflow to Novatak’s terminus, which will hasten a rapid meltdown. The rifts represent places where water level change causes flexure of the glacier, leading to their formation and expansion. They are not related to flow, but to uplift and down fall of ice where it is somewhat afloat. Rapid meltwater inflow to this basin will raise water level further stressing this region this summer. The degree of rifting indicates the ice is thin, but none are open enough to see water. This suggests breakup will not happen this summer. This type of rifting in 2010 and 2015 led to further breakups at Yakutat Glacier.

June 20, 2025 rifting of Novatak Glacier. The rifts represent places where water level change causes flexure of the glacier, leading to their formation and expansion. They are not related to flow, but to uplift and down fall.

Öræfajökull and Vatnajökull, Iceland May High May 2025 Snow Line

On By mspeltoIn Glacier Observations, iceland glacier retreat1 Comment
A view across Jokulsarlon Lagoon toward Fjalljökull and Hrutarjökull of the Öræfajökull Ice Cap on May 25 above. Below, is Skalafellsjokull of Vatnajökull Ice cap on May 26 with Jill and Kevin Duffy in foreground next to lateral moraine (Jill Pelto). Öræfajökull is a connected to Vatnajökull.

Iceland experienced an unusually warm and sunny May, with record high temperatures averaging 10 C above average. This led to a rapid rise in the snow line to elevations more typical of late June than May on the ice caps in southern Iceland, here both Vatnajökull and its southern extension Öræfajökull. We use Sentinel images (Mauri Pelto annotated) and photographs from (Jill Pelto) to illustrate. The University of Maine Sea to Sky Experience explored Iceland in May, and Jill as the artist faculty for the program had a chance to see Iceland with blue sky days.Most days during my two weeks in Iceland were full sun with high temperatures from 10-15 C. The record heatwave reaching into the low 20 C range, rare even for summer here. The lower parts of outlet glaciers already were mostly bare ice, even though melt season should not really have begun yet. Locals were shocked by the weather, and most I heard from were not happy about it, even though it was “nice” out.

On May 20, 2025 the snow line on the southern part of the Öræfajökull Ice Cap averages 800 m, purple dots. SK=Skaftafells, SV=Svinafells, HR=Hrutarjokull, KV=Kviar, FJ=Fjalls, JL=Jokulsarlon Lagoon, H1=Southern Highway.

As May began conditions were typical with the snow line not far from the glacier terminus areas at 350-400 m, May 2 image of Skalafellsjökull. By May 20, the snow line had risen to 750-800 m, a rapid rise of ~400 m in three weeks, represents more than 50% of the rise that should occur by end of summer. By May 26, (Jill image) the snowline had risen further to 800 m+. This snow line elevation is above the typical elevation seen in latter June other years (see below). In 2024 all ten glaciers in Iceland had a negative mass balance (WGMS, 2025). The rapid melt in May 2025, indicates that 2025 will see similar widespread mass loss.

Hrutarjökull with snowline at 800 m on May 26, 2025.
Skalafellsjökull on May 2 and 20, 2025 illustrating rapid snow line rise (yellow dots). Contrast that to the images from mid-late June in 2021 and 2024, below.

Berg Lake, Alaska Evolution Driven by Steller Glacier Retreat

On By mspeltoIn alaska glacier retreat
Berg Lake in 2002 and 2024 Lands at images. Red arrows illustrate 2002 margin, and yellow dots the 2024 margin after a retreat. Yellow arrows indicate the gorge that drained the lake periodically from the 1980s through 2013. Now it drains south sub-glacially into Pacman Lake and then into Bering Lake

Berg Lake is impounded by the Steller Glacier terminus. During the latter half of the 20th century and early 21st century this lake periodically drained west through a gorge to the Bering River. With retreat and thinning this outlet has been abandoned. Vegetation has regrown in portions of this channel area by 2024 illustrating this.

Berg lake and Steller Glacier terminus retreat from 2016 to 2018 in Landsat images exposing the former gorge exit, red arrow.

During the 1986-2022 period the full lake level declined, but the filled area of the lake remained close to 25 km2. The lake level decline led to abandonment of the gorge outlet and drainage south into Lake Ivanov (NWS, 2024). In 2019 this channel was also abandoned, and now the drainage goes directly from Pacman Lake into the Gandil River and then into the Bering River watershed (NWS, 2024). The rapid retreat of Steller Glacier terminus particularly on the western half of more than a kilometer from 2016 to 2018 has driven the continuation of outlet location shift. The speed of drainage from 2018-2021 caused significant flooding in the floodplain of the Bering and Gandil River, that has not been observed in 2022-2024.

Map of Berg Lake drainage path in 2024-yellow dots, false color Sentinel image.

The lake continues to fill each summer and drain in late summer, with drainage being in August of 2021 and 2022, and late July of 2023 and 2024 (NWS, 2024). It is evident that since the 2022 fill of 25 km2, that in 2023 and 2024 the lake did not completely fill before drainage, reducing flood hazards. The minimum lake size has declined as the water level has been reduced to 4 km2 by fall in 2022, 2023 and 2024. The lake depth is greatest in the glacier center, which drives greater calving and retreat. On May 19, 2025 filling is underway and the lake has an area of 6 km2.

Berg Lake in 2022 full in June and drained in October, false color Sentinel images.
Berg Lake drained in September 2023, and filling in June 2024, false color Sentinel images.
Berg Lake in fall 2024 drained and filling in May 2025, false color Sentinel images.

North Cascade Glacier Accumulation Season 2025 and Forecast Outlook

On By mspeltoIn glacier climate change, Glacier Observations, North Cascade Glaciers
As April ends there is a sharp snowline ranging from 1200 m at Mount Baker to 1400 m at Cascade Pass. Above 1500 m the melt season is just getting started.

As the accumulation season comes to an end for North Cascade glaciers it is worth reviewing this winter and looking ahead with a forecast for glacier mass balance by the end of summer 2025. The winter of 2025 at NOAA’s Washington Cascade Mountain West Division 5 records indicate that this winter was below the declining trendline of total precipitation with a mean of 54.8 inches, down slightly from last year. Winter temperatures were again warm at 33.2o F but close to the expected rising trend line average.

The 1946 to 2025 winter (November-March) mean temperature and total precipitation for the Western Cascade Mountains-Division 5 weather stations.

The mean April 1 snow water equivalent (swe) at the six North Cascade Snotel sites with a consistent long term record was 0.72 m. This is below the declining trend line and 31% below the long term average for the 1946-2025 period. This is above the 2024 value, but in the lowest quintile. Mount Baker ski area has reported 585 inches of snowfall through April 21, which is ~30% percentile. April 1 swe is the key date for asssessment for winter snowpack water resources. For glaciers the accumulation season typically continues until the end or April or early May. This year snowpack depth at Mount Baker Ski Area (1280 m) increased from 148 inches on April 1 to 164 inches on April 9 and then declining to 119 inches by May 1 (80% of normal). A similar pattern was seen at Stevens Pass-Grace Lake station (1460 m) with snowpack depth on April 1 of 107 inches, increasing to 114 inches by April 9 and decreasing to 82 inches by May 1. These stations are several hundred meters below glacier elevations. At Lyman Lake Snotel (1800 m) snowpack SWE which most closely matches the glacier elevations was 40.1 inches rising to 42.5 inches by April 11 and declining to 35.9 inches by May 1, ~60% of normal. At the Middle Fork Nooksack site (1520 m) snowpack was 44.8 inches SWE on April 1, rising to 49 inches by April 11 and declining to 46 inches on May 1, 67% of normal . This illustrates that at glacier elevations snowpack would have also increased in mid-April, before a slow decline in the latter part of the month. There were a number of atmospheric rivers that drove a higher snowline than usual as May starts, but also led to a rapid increase in snowpack above the snowline.

The mean April 1 SWE from 1946-2025 at six long term SNOTEL stations: Stampede Pass, Fish Lake, Stevens Pass, Lyman Lake, Park Creek and Rainy Pass.

As the melt season begins, based on the above the winter snowpack on glaciers on May 1 are 70-80% of normal. Eric Gilbertson measured snowpack on the summit Colfax Peak at 17.3 ft (5.27 m) on April 18, 2025. This is a location that is to some extent wind scoured and would be less than the depth on the adjacent glacier, a normal year there is 8-9 m of snowpack at 2300-2800 m. On Eldorado Peak they found 25.3 feet on April 27, 2025. This is the depth expected for this location in a year with 75-80% of normal snowpack. It is a location that appears to balance enhanced deposition and scour. Weather conditions in the Pacific Northwest are forecast to have above average temperatures for the upcoming 90 day period. This combined with the below average snowpack on glaciers on May 1, will yield another year where ice thickness loss exceeds 1 m across the glaciers, as each of the last four years have. The average from 2014-2024 has been -1.41 m, which is a 1.5 thick slice of the glacier lost each year. The range expected this year is -1.2 m to -2.4 m. How much will depend on the specific weather and the frequency and intensity of heat waves.

Mean mass balance observed in the field annually by the North Cascade Glacier Climate Project.

Quelccaya Ice Cap, Peru 25% Snow Cover Retained 2024

On By mspeltoIn climate change glacier retreat, peru glacier retreat1 Comment
Quelccaya Ice Cap in 2013 and 2024 Landsat images illustrating snow line at 5600 m in 2024 and retreat leading to lake expansion at Point A-E from 2013 to 2024.

Quelccaya Ice Cap (QIC) is located in the tropical Andes of southeast Peru. Along with Coropuna Ice Cap it is one of two large ice caps in the area. Lamantia et al (2024) observed a 37% decline overall QIC area from 1985-2022, and a 57% decline in snow covered area. They observe snow cover is particularly limited during El Nino events. Here we examine the particularly high snowline and resulting minimum snow cover on QIC in 2024.

Quelccaya Ice Cap in 2024 August false colar and October natural color Sentinel 2 images. Snow line is at 5600 m in October with 25% snowcover.

The 2023-24 winter season featured El Nino conditions. During spring 2024 El Nino ended and neutral conditions persisted through summer. By late August 2024 the snowline on QIC averaged 5500 m (false color Sentinel Image). By late September 2024 the snowline had risen to ~5600 m, leaving the southern 1/3 and eastern arm of QIC with no snow cover, Landsat image. Overall snowcovered area dropped to ~25%, much below the 75% needed to maintain the ice cap (Lamantia et al. 2024). Despite a few minor snow events that briefly covered the ice cap, in late October the snowline had returned to 5600 m with ~25% snow cover. This is the least extensive snow cover since satellite images allow for mapping in 1984, falling below 10km2 . This is lower than the mininmum of ~15 km2 observed in 2023, which along with 1986 and 2016 had featured the lowest snow covered area on QIC (Lamantia et al. 2024). During this late summer period much of ablation is from sublimation (Fyffe et al 2021).

The high snow line elevation of 2024 exposing the majority of the ice caps glacier ice surface, which melts more rapidly than snow cover, leads to rapid thinning and volume loss.

The series of lakes that began to develop after 1991 at the margin of the QIC have expanded, and now are separating from the retreating ice margin.

Quelccaya Ice Cap in 1991 and 2023 Landsat images illustrating snow line at 5500 m in 2023 and retreat leading to lake development at Point A-E from 1991 to 2024.

Central Andes Glaciers of Chile and Argentina Nearly Snow Free Again in 2025

On By mspeltoIn argentina glacier retreat, chile glacier melt, chile glacier retreat
Alto and Baja del Plomo Glacier in false color Sentinel image from 3-17-2025, expanding bedrock areas amidst upper Baja del Plomo Glacier.

For an alpine glacier to thrive it must remain 50-60% snowcovered throughout the year, even at the end of the summer. To survive it must have consistent significant snowcover at the end of summer, indicative of a persistent accumulation zone (Pelto, 2010). In the Central Andes of Argentina and Chile I have chronicled the near total loss of snowpack, leading to dirty/dark snowcover free glaciers. in 2022 and 2023 (Pelto, 2023). In 2025 this pattern is again apparent. From north of Santiago at Olivares Glaciers and Alta/Baja de Plomo Glacier to east of Santiago at Volcan Overo adn Fiero Glacier to south of the Santiago region at Cobre Glacier and Volcan Peteroa we see glaciers in mid-March with less than 10% snowcover remaining. This is indicative that the 2024/25 mass balance period for the Central Andes will be one of significant loss.

Olivares Glaciers and Juncal Sur in in false color Sentinel image from 3-17-2025,
Volcan Overo Glaciers in false color Sentinel image from 3-17-2025, continued fragmentation and expanded bedrock area amidst glaciers evident.
Del Humo and Fiero Glacier in false color Sentinel image from 3-17-2025.
CobreaGlacier in false color Sentinel image from 3-17-2025, is retreating both at the top (northwest) and terminus (southeast) of the glacier.
Volcan Peteroa Glaciers in false color Sentinel image from 3-17-2025.

World Day For Glaciers March 21 2025

On By mspeltoIn Glacier Observations

March 21, 2025, the “World Day for Glaciers”, is part of the UN International Year for Glaciers’ Preservation.” Rapid and accelerating glacier loss this century led to this day. In 2023 and 2024 for the first time all 58-reporting Global Reference glaciers had a negative mass balance. Acceleration of glacier’s disappearing led to creation of an extinct glacier data layer in GLIMS global glacier inventory. 

To preserve a glacier, we have to understand how a glacier is formed. Easton Glacier, Mount Baker is our sample location, we’ve monitored this Global Reference for four decades. Easton still has an accumulation zone and may survive current climate at a reduced size. We’ve observed 28 North Cascade glaciers disappear this century, including Ice Worm Glacier after visiting every year for 40 years, lost in 2023. 

Recipe: Creating a North Cascade Glacier 

  • Location with cold temperatures 7+months/year.  
  • Substantial snowfall 10 m on slope of 10-30O. 
  • Let stand 2-4 decades, with melting, refreezing and burial creating dense ice, until thickness exceeds 20 m and a volume over 500,000 m3. 
  • Movement will commence and crevasses develop. 

Snowmaking  

  • Easton Glacier area is 2.5 km2 and is losing 1.5 m water equivalent thickness annually, this is 3.75 million m3 of water equivalent snow. 
  • Largest snow making operation is Killington, VT, daily maximum capacity of 35,000 m3 of water converted to snow. 
  • At max-capacity the 2000+ snow guns require 108 days to produce 3.75 million m3. 
  • Address environmental laws and logistics of deployment and maintenance for water piping, snow gun placement and electricity in harsh environment of avalanches and crevasses. 

Geotextile: 

  • Cover 1.5 million m2 (60%) of Easton Glacier with geotextiles installed each summer and removed in winter. 
  • Summer recreation would no longer viable.  
  • The short-lived geotextiles cost ~$2 m2.  
  • Anchoring and connecting on a crevassed glacier very difficult,  

Renewables: 

  • When I began in 1984 solar and wind power were not significant electricity sources. 
  • Global Solar Photovoltaic energy production capacity rose from 4 GW in 2004 to 1600 GW in 2023. 
  • Global Wind power capacity rose from 48 GW in 2004 to 1070 GW in 2023. 
  • With 500 MW added in 2023 this is a preservative that can work in concert with power grid improvement.  

Darwin Glacier, Sierra Nevada, California No Longer a Surviving Glacier

On By mspeltoIn california glacier melt
Darwin Glacier on 8-29-2022 in Sentinel False Color image with area reduced to 0.026 km2. No longer a glacier there is still relict ice clinging to the slope, in the next six weeks further melt reduced volume significantly.
Darwin Glacier on July 19, 2022 with the moraine that the glacier was in contact with in the 1990s-yellow dots, and curent margin green dots. The blue arrows indicate rock area emerging as glacier thins. Slope has steepened and bergshrund is melting out (sierralara.com, image)

The Sierra Nevada, California has a number of small glaciers that have clung to the north facing slopes of the High Sierra. Darwin Glacier is one of those glaciers on the north side of Mount Darwin. named for Charles Darwin. The glacier is in Kings Canyon National Park and drains into the San Joaquin River.

In 1903 the glacier had an area of 0.25 km², declining 40% by 1948, 0.14 km2 Basagic and Fountain (2011). The glacier expanded beginning in the 1970s and ending in the 1990s, with an area of 0.157 km² in 1976 (GLIMS), and then had declined slightly in 2001 had an area of 0.135 km², 5-10% greater than in 1948. In 2004 area loss was increasing with the area measured in the field by Basagic and Fountain (2011), at 0.114 km2 .

With a steep slope of ~30 degrees, the glacier depends on snow sloughing/avalanching off the north face of Mount Darwin and piling up against a moraine. Retreat from this moraine after 2004 has led to steepening of the glacier with less snowcover retained on its surface. From 2004 to 2022 the glacier rapidly lost volume and area. In 2014 the glacier area had declined 50% to 0.057 km² (GLIMS), in 2018 the glacier area was 0.048 km². The particularly warm summers of 2021 and 2022 led to further rapid decline to 0.038 km² in 2021 and 0.026 km² in 2022. At this time Darwin Glacier and was no longer a glacier with less than 20% of relict ice left from 2004, and with movement having ceased. The glacier bergshrund is also melting out. Bare rock was was also being exposed at several areas amidst the glacier area in 2022.

Just to the south Mount Fiske Glacier has disappeared as well, along with the glacier that was in the cirque on the north side of Mt. Mendel. The high snowfall winters of 2023 and 2024 have been offset by continued warm summers, preventing any significant volume increase.

Darwin and Mt. Fiske Glacier on 1976 USGS Topographic map with areas of 0.16 km2 and 0.08 km2 respectively.
Darwin Glacier in 2018 Sentinel false color image with an area of 0.048 km2.
Darwin Glacier and Fiske Glacier no longer have sufficient area to qualify as glaciers at 0.026 km² for Darwin Glacier and 0.008 km² for Fiske Glacier. No retained snowcover in 2021 or 2022.
Darwin Glacier on August 29, 2021 in Sentinel false color image. There is no retained snowcover and area has declined to 0.036 km2.
Darwin Glacier on August 28, 2024 in Sentinel false color image. There are two areas where area loss from 2022 is evident, despite 60% of the glacier still having snow cover.

These losses are similar to those observed on Whitney Glacier, Mount Shasta. The NCEI NOAA Division 5 climate data for this area indicates that meltseason temperatures have been the primary cause of the recent decline, though declining accumulation season precipitation has been as well, see bottom.

California Division 5 Average Temperature May-September 1950-2022.

Ice Worm Glacier Disappears in 2023, North Cascade Range, WA

On By mspeltoIn climate change glacier retreat, Glacier Observations, North Cascade Glaciers
Ice Worm Glacier from the same location in 1986 and 2023, Bill Prater in 1986 image.

Ice Worm Glacier is an east-facing cirque glacier on the east flank of Mount Daniel, WA. Mount Daniel is on the crest of the North Cascade Range of Washington, the crest separates the dry east side that drains to the Columbia River and the wet west side that drains to Puget Sound. The glacier is at the headwaters of Hyas Creek, which drains into the Cle Elum River and the Cle Elum Reservoir. The Cle Elum Reservoir has a storage volume of 538,900,000 m3 and is primarily used for flood control in spring, and agricultural irrigation in summer. This reservoir is the largest in the Yakima River Basin and provides irrigation to 180,000 hectares of agricultural land. The glacier is located in the Alpine Lakes Wilderness area which prohibits the use of mechanized equipment. The Ice Worm Glacier cirque floor is at 1940 m and the headwall at 2050 m. There is a bench at 2150–2300 m that held a glacier/perennial icefield prior to 2015. The glacier is accessed by backpacking 8 km from the Cathedral Rock trailhead with the same base camp used each year at 1700 m on the bank of Hyas Creek. Detailed publication by Mauri and Jill Pelto at: Loss of Ice Worm Glacier, North Cascade Range, WA USA, 2025.

The glacier is fed by wind drift accumulation along the ridge that was just above the top of the glacier during the 1944-2000 period. Avalanching from the slopes below the East Peak of Mount Daniel and from the ridges extending along the north and south flank of the glacier have also been significant. The glacier is part of the Mount Daniel-Mount Hinman Glacier Complex just south of Highway 2 and sits astride the Cascade Divide. This complexcomprised of 9 glaciers covering 3.8 km2 in 1984. This was the biggest cocentration of glaciers between Mount Rainer and Glacier Peak. At the end of the summer 2023 melt season only three of these remain as glaciers, Daniels, Foss and Lynch Glacier. We began monitoring these glaciers along with Ice Worm Glacier in 1984.

Ice Worm Glacier Evolution

Ice Worm Glacier field sketch by Jill Pelto in 2023.

In 1986 William (Bill) Prater, who had made many first ascents in the area between 1944 and 1960, joined us in the field. Bill also had invented and patented (1973) the first snowshoe with a claw attached to its binding, the Sherpa Snowshoe. Comparing images from these early visits with the current margin of Ice Worm Glacier indicated that there had little change in this glacier from 1944-1986. The mapped area in 1958 was 0.19 km2 (GLIMS, 2023), in 1986 we mapped the area at 0.18 km2.

Each summer during the third week in August we measure the mass balance of this glacier. Because the glacier lacks crevasses we simply grid the glaciers with measurements made 50 m apart along transects running up the glacier and across the glacier along the margins. We also completed a longitudinal profile running up the glacier from a fixed location on the bedrock at the below and at the top of the glacier. The surface elevation was determined at the specific 50 m points to identify thinning of the glacier. During the first decade the glacier extended to within 10 m of the ridge on the south side of the glacier, allowing us to ski off of the ridge, see 1990 image below.

Glacier Area Change

View of the south ridge across Ice Worm Glacier in 1990 above and 2006 below, note recession of the top of the glacier from this ridge.

From 1984 to 1992, the glacier extended to within 15 m of the ridge on the south side of the basin. By 1995 this was no longer possible as the top of the glacier was retreating as fast as the bottom of the glacier. In 2006, the recession from this ridge was greater than the recession at the terminus. The glacier perimeter was surveyed in the low snow years of 2005 and 2015, identifying the glacier area to be 0.15 km2 and 0.110 km2, respectively. In 2015, the inventory for RGI noted an area of 0.106 km2. Annually, from 2021 to 2024, low snow cover allowed for mapping of the glacier perimeter during a rapid decline from 0.09 km2 to 0.03 km2. The area loss from 1986 to 2015 was 0.07 km2, which is less than the area loss from 2015 to 2023 of 0.08 km2. provides a photo comparison of the change from 1986 to 2023, with the people standing in the same location in each case. The observed area determined in the field from the GPS position locations closely matches the RGI inventory area in 2015 and the area derived from overlaying the points on Sentinel 2 imagery from August 2021 to 2024, which have a 10–30 m resolutionThis summer we observed a dozen holes that reached the bottom of the glacier 4-6 m below, indicating how thin the ice is. There is no movement, the size and thickness are too low to generate future movement, hence this is no longer a glacier. A glacier is a body of snow and ice that is moving, this requires a persistent thickness of 20-30 m, which is typically associated with snow/ice areas of ~50,000 m² or larger. As a glacier becomes thinner or smaller than this movement will not be sustained.

Table 1. The observed area of Ice Worm Glacier from field measurements. The area of Ice Worm Glacier from previous inventories and Sentinel 2 imagery.

YearField Mapped Area (m2)Validating Aerial/Satellite Image Area (m2)
1958 190,000 (GLIMS)
1986180,000 (±10,000)Field Observation only
1992170,000 (±10,000)Field Observation only
2005150,000 (±5000)Field Observation only
2015110,000 (±5000)106,000 (RGI)
202188,000 (±2000)90,000 (Sentinel)
202268,000 (±2000)Field Observation only
202341,000 (±2000)40,000 (Sentinel)
202432,000 (±2000)30,000 (Sentinel)

We have measured discharge at a natrual weir below Ice Worm Glacier since 1986. Average August daily runoff has declined 60% by 2022.

Glacier Base Observations

Ice Cave in 2024 that extended from top to the end of the glacier.

Beginning in 2015, we routinely assessed how deep each moulin, crevasse or supraglacial stream channel was on the glacier. One measure of a glacier no longer being a glacier is when crevasse features and stream channels consistently reach the bedrock below the glacier. In 2023, we examined 24 of these features and each reached bedrock at depths of 2–10 m. These features were distributed widely across the glacier. There are undoubtedly limited areas of thicker ice. In 2024, we explored an ice cave that extended 250 m from the top of the glacier to the end of the glacier. The cave roof was 1–4 m above bedrock, and the roof was consistently less than 2 m thick allowing light to penetrate from the glacier surface into the cave. An extensive ice cave transecting the entire glacier such as this cannot exist in a current glacier because ice movement would lead to ice cave closure.

Streams channel reaching bedrock at base of Ice Worm Glacier.

Each year in mid-August, stream discharge has been observed immediately below the 1986 terminus position of Ice Worm Glacier at 11 a.m., 2 p.m. and 5 p.m. during the field visit. This stream is also fed by perennial snowfields and, before 2015, a small glacier. These observations are insufficient to quantify daily runoff, but because of the consistent timing and methods, do allow for comparison. The glacier is located on the dry side of the range and has not experienced rainfall during any of our field observation periods, which would contribute to stream discharge. From 1985 to 2002, streamflow was observed on 36 days, with the average discharge being 0.12 m3 s−1. From 2021 to 2024, discharge was observed on 6 days with the average discharge being 0.03 m3 s−1. This roughly 75% decline in August runoff is similar to the 60% loss in runoff modeled for the loss of small glaciers in basins in the Alps and observed when the Lewis Glacier, North Cascade Range was lost. The change in summer streamflow in Hyas Creek near our base camp is apparent, as it had been a challenging stream crossing to keep your feet dry until 2013, and now is a simple step across. There has also been a marked increase in algae coating the substrate of the stream with the lower flow, clearer and warmer water, which is expected.

Climate Drivers

Trends in summer temperature at Western Cascade weather stations for the 1896 to 2024 period indicate that seven of the ten warmest melt seasons (June–September) have occurred since 2013. Melt season temperatures from 2014 to 2024 were 1.3 °C above the 1896 to 2022 mean. The long-term winter temperature trend from 1896 to 2024 has been 1.2 °C. From 2014 to 2024 winter temperatures were 0.9 °C above the long-term average, the warmest decadal period of the record.

During the 1896 to 2024 period from June to September, precipitation exhibited no significant trend. For the November–April (winter season) there was a 3% increase in precipitation from 1896 to 2024. From 2014 to 2024 winter precipitation averaged 1.68 m vs. the long-term average of 1.65 m. April 1 SWE from six long-term SNOTEL stations where April 1 SWE has a declining trend of 30% from 1946 to 2023, with a 10% decline since 1984. The April 1 SWE loss reflects increased melting of the snowpack or rain events during the winter season.This indicates that it is temperature rise that is driving the glacier mass balance loss, retreat and eventual disappearance of Ice Worm Glacier.

Washington State Division 5 -Cascade West-Temperature trends.
Washington State Division 5 -Cascade West-Precipitation trends.

Burroughs Glacier, Alaska Vanishing

On By mspeltoIn alaska glacier retreat, Glacier Observations

Burroughs Glacier in 1986 and 2024 Landsat images. The red arrow marks terminus in 1986 and yellow arrows the 2024 terminus. Yellow dots mark the outline of the glacier in 2022. Glacier area declined from 12.5  km² to 1.2 km² during this 38 year period.

Burroughs Glacier in Glacier Bay National Park, Alaska has been retreating since 1892 when it was part of the Muir Glacier complex. The glacier is named for naturalist John Burroughs, who accompanied John Muir to the areain 1899 on the Harriman Expedition. The glacier is unusual in that it has not had an accumulation zone this century, where snow persists through the year. Without an accumulation zone a glacier cannot survive (Pelto, 2010). Mickelson (1971) summarized the retreat of the glacier from 1892-1960. In 1892 the Burroughs ice plateau was assessed as a 10 km by 25 km ice cap. By 1960 it had thinned by as much as 750 m and its calving margin had retreated 27 km. In the 1960s crevasse extension were still active (Taylor, 1963). By the end of the 1970’s the glacier was essentially stagnant (Molnia, 2008). In 1982 I briefly visited the western terminus, which provided a still imposing slope, made more so by the rain and clouds lowering onto its surface, active crevasses were still evident indicating some movement. John Burroughs in writing the narrative of the Harriman Expedition noted about vanishing glaciers “It is dead or motionless, and is therefore free from crevasses. Its rim comes down to the gravel like a huge turtle shell and we stepped up on it without difficulty. (page 45)”.

Here we examine the glacier in Landsat imagery from 1986 to 2024to illustrate the retreat, the lack of snowcover  and the thinning. In the 1948 map of Burroughs Glacier, the glacier is 12.1 km long, and much of the glacier is already stagnant, the glacier has both a north and south terminus, purple arrows.

burroughs map

Burroughs Glacier in 1948 USGS map. Purple arrow indicate terminus locations. Former Plateau Glacier (P).

In 1948 Burroughs Glacier has an area of 22 km² and is 12.5 km long, with the crest of the glacier at 425 m. In 1986 Burroughs Glacier has an area of 12.5 km² and has no snowcover by mid-summer. The glacier terminates in proglacial lakes at both the north and south terminus and is 9 km long, purple arrows indicate 1948 terminus. In 2004 Burroughs Glacier again lacks any snowcover. The southern terminus has retreated 2.2 km from the lake, and the northern terminus has retreated into a second lake basin. The glacier is 6.3 km long, half of its length in 1948. In 2010 snowcover is lacking and retreat has continued shrinking the glacier to 5.4 km in length.  The glacier was assessed with an area of 2.9 km² and a median elevation of  313 m (1025 feet) by GLIMS, in 2010.  In 2013 the glacier lacks snowcover in this September Landsat image even though snow has returned to the surrounding mountains. This indicates how far below the snowline the glacier lies. Portions of a glacier are supposed to be the first locations that receive snowcover. The terminus has continued to retreat and the glacier was 4.6 km long in 2013. The northern terminus was retreating into a third basin of the proglacial lake. By 2018 the glacier area has been reduced to 2.7 km², then 1.5 km² in 2022 and 1.2 km² in 2024., 5.5% of its area remaining from 1948, 10% of its area from 1986 and 1% of the 1892 area.  The length of the glacier in 2024 is 2.3 km, only 50% of the length just a decade ago, and ~20% of the 1948 length.

Thinning of this glacier from 1948-2016 is evident from a comparison of topographic maps. Thinning in remaining glacier are averages 225 m during this period, that is a rate of ~3.3 m/year. Larsen et al (2007) had found a thinning rate of ~3 m/year for the 1948-2000 period. Satellite imagery allows identification of glacier area, which declined at a linear rate from 2004-2024, correlation coefficient of 0.98. This his linear rate indicates the glacier will disappear in 2029 or 2030.

Burroughs Glacier has not been in equilibrium with climate the past century. Its retreat has been hastened by the rising snowline of the last decade note by Pelto et al (2013) on Brady Glacier. This glacier area has declined by 90% since 1986, with volume loss being even larger.  Retreat usually increases as elevation declines and as the size of the remnant ice declines. There is no debris cover or persistent snowcover to slow the loss.

Overlay of 1948 (blue labeled contours) and 2014 elevation map (brown labeled contours) for Burroughs Glacier.

Burroughs Glacier area from Landsat and Sentinel images from 2004 to 2024. This is a strongly linear decrease, that projected beyond 2024 hits bottom in 2029 or 2030.

2004 Landsat image of Burroughs Glacier. The red arrow marks the west margin in 1986 and the yellow arrow the east margin.

2010 Landsat image of Burroughs Glacier. The red arrow marks the west margin in 1986 and the yellow arrow the east margin.

2013 Landsat image of Burroughs Glacier. The purple arrows mark the 1948 margin, red arrow the west margin in 1986 and the yellow arrow the east margin in 1986, pink arrows the 2013 margin.

2022 false color Sentinel image of Burroughs Glacier. The ice is dirty but not debris covered at this point, glacier area 1.5 km2.

2018 and 2024 false color Sentinel image of Burroughs Glacier. The ice is dirty but not debris covered. Area declined from 2.7 km2 to 1.2 km2