Mauri S. Pelto is a professor of environmental science at Nichols College in Dudley, Massachusetts and director of the North Cascades Glacier Climate Project. [1]
Mauri S. Pelto is a professor of environmental science at Nichols College in Dudley, Massachusetts and director of the North Cascades Glacier Climate Project. [1]
Mauri Pelto has been studying the glaciers in the North Cascades located in the U.S. state of Washington since 1984. [1] Pelto's research team has recorded the mass balance of numerous glaciers, all of which are retreating due to global warming, which has raised temperatures and decreased the amount of snowfall in the accumulation zone of the North Cascade glaciers. More recently, Pelto has used Landsat imagery from the past and compared it to more recent imagery to make comparisons between the extent of glacial coverage over periods spanning decades. [1]
Pelto has stated that of the 756 glaciers that were identified in the North Cascades by the U.S. Geological Survey in 1971, 53 of them had disappeared completely by 2006. Another nine are also expected to disappear if current climate patterns continue. [2] In addition, three glaciers in particular pose economic and environmental risks if they retreat much further. [3]
The Mount Baker–Snoqualmie National Forest in Washington is a National Forest extending more than 140 miles (230 km) along the western slopes of the Cascade Range from the Canada–US border to the northern boundary of Mount Rainier National Park. Administered by the United States Forest Service, the forest is headquartered in Everett. There are local ranger district offices in North Bend and Skykomish.
Crucial to the survival of a glacier is its mass balance of which surface mass balance (SMB), the difference between accumulation and ablation. Climate change may cause variations in both temperature and snowfall, causing changes in the surface mass balance. Changes in mass balance control a glacier's long-term behavior and are the most sensitive climate indicators on a glacier. From 1980 to 2012 the mean cumulative mass loss of glaciers reporting mass balance to the World Glacier Monitoring Service is −16 m. This includes 23 consecutive years of negative mass balances.
The retreat of glaciers since 1850 is well documented and is one of the effects of climate change. The retreat of mountain glaciers, notably in western North America, Asia, the Alps and tropical and subtropical regions of South America, Africa and Indonesia, provide evidence for the rise in global temperatures since the late 19th century. The acceleration of the rate of retreat since 1995 of key outlet glaciers of the Greenland and West Antarctic ice sheets may foreshadow a rise in sea level, which would affect coastal regions. Excluding peripheral glaciers of ice sheets, the total cumulated global glacial losses over the 26-year period from 1993 to 2018 were likely 5500 gigatons, or 210 gigatons per yr.
Chocolate Glacier is located on east slopes of Glacier Peak in the U.S. state of Washington. The glacier descends from 10,400 ft (3,200 m) to 5,900 ft (1,800 m) and is partially connected to Cool Glacier which lies to its south just below the summit of Glacier Peak. As is true with all the glaciers found on Glacier Peak, Chocolate Glacier is retreating. Chocolate Glacier retreated approximately 1,380 m (4,530 ft) between 1906 and 1946, however during a cooler and wetter period from about 1950 to 1979, the glacier advanced 450 m (1,480 ft). Chocolate Glacier has resumed retreating since and has given back 350 m (1,150 ft), nearing its previously recorded minimal length. The current terminus at 1800 m is still the lowest of the east side glacier. Chocolate Glacier remains heavily crevassed and active to 1900 m. The lowest 300 m of the glacier are stagnant.
Cool Glacier is located on east slopes of Glacier Peak in the U.S. state of Washington. The glacier descends from 10,200 ft (3,100 m) to 6,900 ft (2,100 m) and is partially connected to Chocolate Glacier which lies to its north just below the summit of Glacier Peak. As is true with all the glaciers found on Glacier Peak, Cool Glacier is retreating. Cool Glacier retreated approximately 1,500 m (4,900 ft) between 1850 and 1946, however during a cooler and wetter period from about 1950 to 1979, the glacier advanced. Since then Cool Glacier resumed retreating and by 2005 the glacier was within 40 m (130 ft) of its minimum length recorded in 1946.
North Guardian Glacier is located on east slopes of Glacier Peak in the U.S. state of Washington. The glacier descends from 8,600 ft (2,600 m) to 6,430 ft (1,960 m) and is partially connected to Chocolate Glacier which lies to its south. As is true with all the glaciers found on Glacier Peak, North Guardian Glacier is retreating. North Guardian Glacier retreated approximately 1,500 m (4,900 ft) between 1850 and 1946, however during a cooler and wetter period from about 1950 to 1979, the glacier advanced modestly. Since then North Guardian Glacier resumed retreating and thinning and by 2005 the glacier had returned to its minimum length as recorded in 1946.
Dusty Glacier is located on northeast slopes of Glacier Peak in the U.S. state of Washington. The glacier descends from 9,022 ft (2,750 m) to 6,430 ft (1,960 m) and in places along its length is connected to North Guardian Glacier which lies to its south and Ermine Glacier to the north. As is true with all the glaciers found on Glacier Peak, Dusty Glacier is retreating. During the Little Ice Age, Dusty Glacier extended down to an altitude of 4,800 ft (1,500 m), but since approximately the year 1850, the glacier has been in a general state of retreat and has lost more than 1,500 m (4,900 ft) of its length. Dusty Glacier is heavily crevassed and the glacier ends in an ice fall at its terminus.
Ermine Glacier is located on north slopes of Glacier Peak in the U.S. state of Washington. As is true with all the glaciers found on Glacier Peak, Ermine Glacier is retreating. During the Little Ice Age, Ermine Glacier extended down to an altitude of 4,400 ft (1,300 m) and was connected to Vista Glacier to its west. From the end of the Little Ice Age to the mid-1950s, Ermine Glacier experienced a general retreat upslope, followed by an advance during a cooler and wetter period until the mid-1970s. However, between 1992 and 2005, Ermine Glacier again retreated 308 m (1,010 ft).
Scimitar Glacier is located on the west and northwest slopes of Glacier Peak in the U.S. state of Washington. As is true with all the glaciers found on Glacier Peak, Scimitar Glacier is retreating. During the Little Ice Age Scimitar Glacier was connected to Kennedy Glacier to the north. From about 1850 to 1946, the glacier retreated 5,250 ft (1,600 m), but advanced 1,738 ft (530 m) during a colder and wetter period lasting until about 1980. Scimitar Glacier has retreated since, but due to the thickness of the ice at the terminus, had not lost much of its length through the year 2005.
Honeycomb Glacier is located in the Glacier Peak Wilderness in the U.S. state of Washington. The glacier is mainly in Mount Baker-Snoqualmie National Forest, but a small segment near the top of the glacier extends into Wenatchee National Forest. Honeycomb Glacier is nearly connected to White River and Suiattle Glaciers and is separated from them by an arête off the Kololo Peaks. Honeycomb Glacier is one of the largest glaciers found in the North Cascades, but since the end of the Little Ice Age, retreated 1.08 mi (1.74 km) between then and the year 2005. More than a quarter of the retreat happened between 1979 and 2005, suggesting that the rate of recession has been increasing.
Milk Lake Glacier is located in the Glacier Peak Wilderness in the U.S. state of Washington. The glacier is within Mount Baker-Snoqualmie National Forest and a little over 3 mi (4.8 km) northwest of Glacier Peak. Milk Lake Glacier disappeared sometime between 1984 and 1997 and by 2005, Milk Lake was situated where the glacier had once been.
Suiattle Glacier is located in the Glacier Peak Wilderness in the U.S. state of Washington. The glacier is within Mount Baker-Snoqualmie National Forest and nearly touches Honeycomb and White River glaciers separated from them by an arête off the Kololo Peaks at its uppermost reaches. Suiattle Glacier has retreated significantly since the end of the Little Ice Age, and from approximately the years 1850 to 1924 lost 1,400 m (4,600 ft) of its length. Between 1924 and 1940, the glacier retreated an additional 900 m (3,000 ft), then during a cooler and wetter period between 1967 and 1979, the glacier had a small advance of 20 m (66 ft). After this, Suiattle Glacier began to retreat again and has retreated 270 m from its advanced position in the 1970s to 2009.
White Chuck Glacier is located in the Glacier Peak Wilderness in the U.S. state of Washington and is 3.5 mi (5.6 km) south of Glacier Peak. The glacier is within Mount Baker-Snoqualmie National Forest and nearly touches the White River Glacier though they are separated by an arête off the Kololo Peaks. White Chuck Glacier has retreated significantly since the end of the Little Ice Age. From about 1850 to 1930, the glacier thinned and by 1940, a fast rate of retreat commenced. By 1955, the glacier had three separate termini and by 2005, the northern terminus was gone. Several small proglacial lakes have been left behind by the retreating glacier. Between 1958 and 2005 White Chuck Glacier lost more than half its surface area.
Boston Glacier is located in a large cirque below several mountain peaks in North Cascades National Park in the U.S. state of Washington. Approximately 1 mi (1.6 km) long but nearly 3.5 mi (5.6 km) wide, it is the largest glacier in North Cascades National Park. Extending in an arc from the north of Forbidden Peak, it is flanked by Boston Peak to the southwest and Buckner Mountain at its eastern margin, between which it lies below the arête known as Ripsaw Ridge. Another arête extending between Boston Peak, Sharkfin Tower, Forbidden Peak and further north separate Boston Glacier from the nearly adjoining Quien Sabe and Forbidden Glaciers. Boston Glacier has been in an overall state of retreat since the end of the Little Ice Age around the year 1850. A moderate advance occurred between 1950 and the mid-1970s; however, the retreat resumed and between 1972 and 2006 its terminus retreated 1,470 ft (450 m).
Hinman Glacier was a glacier that flowed to the north and northwest from near the summit of Mount Hinman, in the U.S. state of Washington. Hinman Glacier was within the Alpine Lakes Wilderness of Snoqualmie National Forest. The glacier was approximately 1.3 km2 in 1971, making it the largest glacier between Mount Rainier and Glacier Peak, but an expedition by glaciologists from Nichols College in August 2022 discovered that the glacier had disappeared, with only a few snowfields and non-flowing remnant ice areas totalling 0.04 km2 remaining. Smaller glaciers in this part of the Cascade Range preceded the Hinman Glacier in disappearing as part of the retreat of glaciers since 1850 with only three glaciers remaining in King County.
Middle Cascade Glacier is in Wenatchee National Forest in the U.S. state of Washington and is to the north of Spider Mountain and east of Mount Formidable. Middle Cascade Glacier has a significant icefall that is thinning and may eventually separate the upper section of the glacier from the lower. Middle Cascade Glacier retreated 260 m (850 ft) between 1979 and 2005. The smaller Spider Glacier is just southeast of Middle Cascade Glacier.
Hidden Creek Glacier is in North Cascades National Park in the U.S. state of Washington and is on the northwest slope of Hagan Mountain. Retreat of this glacier from 1979 to 2005 exposed several rock outcroppings in the middle of the glacier. The terminus of Hidden Creek Glacier only retreated 50 m (160 ft) between 1979 and 2011, however the increase in area of exposed rock outcroppings in the middle of the glacier indicates rapid thinning.
Daniel Glacier is in Wenatchee National Forest in the U.S. state of Washington and is on the north slope of Mount Daniel. Daniel Glacier retreated almost 500 m (1,600 ft) between 1950 and 2005. Daniel Glacier is separated from Lynch Glacier to the west by a ridge.
Foss Glacier is within the Alpine Lakes Wilderness of Snoqualmie National Forest in the U.S. state of Washington and is on the northeast slope of Mount Hinman. Foss Glacier retreated almost 500 m (1,600 ft) between 1950 and 2005. Foss Glacier is separated from the nearly vanished Hinman Glacier to the west by a ridge.
Cache Col Glacier is in North Cascades National Park in the U.S. state of Washington, on the east slope of Mix-up Peak. Cache Col Glacier retreated nearly 100 m (330 ft) between 1950 and 2005. Cache Col Glacier is 1 mi (1.6 km) northwest of Yawning Glacier.
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