A glacier is a persistent body of dense ice that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as crevasses and seracs, as it slowly flows and deforms under stresses induced by its weight. As it moves, it abrades rock and debris from its substrate to create landforms such as cirques, moraines, or fjords. Although a glacier may flow into a body of water, it forms only on land and is distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water.
Mount Shasta is a potentially active stratovolcano at the southern end of the Cascade Range in Siskiyou County, California. At an elevation of 14,179 ft (4,322 m), it is the second-highest peak in the Cascades and the fifth-highest in the state. Mount Shasta has an estimated volume of 85 cubic miles, which makes it the most voluminous volcano in the Cascade Volcanic Arc. The mountain and surrounding area are part of the Shasta–Trinity National Forest.
Hubbard Glacier is a glacier located in Wrangell–St. Elias National Park and Preserve in eastern Alaska and Kluane National Park and Reserve in Yukon, Canada, and named after Gardiner Hubbard.
Mendenhall Glacier is a glacier about 13.6 miles (21.9 km) long located in Mendenhall Valley, about 12 miles (19 km) from downtown Juneau in the southeast area of the U.S. state of Alaska. The glacier and surrounding landscape is protected as part of the 5,815 acres (2,353 ha) Mendenhall Glacier Recreation Area, a federally designated unit of the Tongass National Forest.
Tasman Glacier is the largest glacier in New Zealand, and one of several large glaciers which flow south and east towards the Mackenzie Basin from the Southern Alps in New Zealand's South Island.
The Greenland ice sheet is an ice sheet which forms the second largest body of ice in the world. It is an average of 1.67 km (1.0 mi) thick, and over 3 km (1.9 mi) thick at its maximum. It is almost 2,900 kilometres (1,800 mi) long in a north–south direction, with a maximum width of 1,100 kilometres (680 mi) at a latitude of 77°N, near its northern edge. The ice sheet covers 1,710,000 square kilometres (660,000 sq mi), around 80% of the surface of Greenland, or about 12% of the area of the Antarctic ice sheet. The term 'Greenland ice sheet' is often shortened to GIS or GrIS in scientific literature.
The Columbia Glacier, a glacier in Prince William Sound on the south coast of the U.S. state of Alaska, is one of the fastest moving glaciers in the world, and has been retreating since the early 1980s. It was named after Columbia University, one of several glaciers in the area named for elite U.S. colleges by the Harriman Alaska Expedition in 1899. The head of the main branch of the glacier originates at the saddle between Mount Witherspoon and Mount Einstein.
Thwaites Glacier is an unusually broad and vast Antarctic glacier located east of Mount Murphy, on the Walgreen Coast of Marie Byrd Land. It was initially sighted by polar researchers in 1940, mapped in 1959–1966 and officially named in 1967, after the late American glaciologist Fredrik T. Thwaites. The glacier flows into Pine Island Bay, part of the Amundsen Sea, at surface speeds which exceed 2 kilometres (1.2 mi) per year near its grounding line. Its fastest-flowing grounded ice is centered between 50 and 100 kilometres east of Mount Murphy. Like many other parts of the cryosphere, it has been adversely affected by climate change, and provides one of the more notable examples of the retreat of glaciers since 1850.
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.
Jakobshavn Glacier, also known as Ilulissat Glacier, is a large outlet glacier in West Greenland. It is located near the Greenlandic town of Ilulissat and ends at the sea in the Ilulissat Icefjord.
The retreat of glaciers since 1850 is a well-documented effect of climate change. The retreat of mountain glaciers provide evidence for the rise in global temperatures since the late 19th century. Examples include mountain glaciers in western North America, Asia, the Alps in central Europe, and tropical and subtropical regions of South America and Africa. Since glacial mass is affected by long-term climatic changes, e.g. precipitation, mean temperature, and cloud cover, glacial mass changes are one of the most sensitive indicators of climate change. The retreat of glaciers is also a major reason for sea level rise. Excluding peripheral glaciers of ice sheets, the total cumulated global glacial losses over the 26 years from 1993 to 2018 were likely 5500 gigatons, or 210 gigatons per year.
The Mud Creek Glacier is the southernmost glacier on Mount Shasta in the U.S. state of California. It lies to the east of Sargents Ridge on Shastarama point near 10,915 feet (3,327 m) above sea level. The glacier is smaller than the northern ones on Mount Shasta such as Whitney, Hotlum, Bolam, and Wintun Glaciers. There are approximately 80 glaciers in California and unlike the glaciers in Alaska, Colorado and Montana. California’s existing current glaciers are not remnants of the Pleistocene, but instead relatively young approximately 1,000 years in age. The Mud Creek Glacier is one of at least 7 recognized glaciers on Mt. Shasta by the United States Geological Survey (USGS) the rest being: Whitney, Hotlum, Bolam, Wintun, Konwakiton, and Watkins.
The Hotlum Glacier is a glacier situated on the northeast flank of Mount Shasta, in the US state of California. It is the largest and most voluminous glacier in California, although not as thick or long as the nearby Whitney Glacier. The Hotlum Glacier flows from a large cirque on the northeast side of Mount Shasta's main summit below the Hotlum Headwall at roughly 13,600 ft (4,100 m). It flows northeastward down the steep slope, forming three lobes which terminate near 10,400 ft (3,200 m).
The Bolam Glacier is a glacier situated on the northern flank of Mount Shasta, in the U.S. state of California. It is the second longest glacier in California behind the nearby Whitney Glacier, and the fourth largest and most voluminous after the neighboring Hotlum Glacier, Whitney Glacier, and Wintun Glacier. The Bolam Glacier flows from a cirque on the north side of Mount Shasta's main summit, with the moving ice starting below a large bergschrund which spans the glacier at 12,600 ft (3,800 m). Above that, permanent snow and ice extends towards the summit to about 13,500 ft (4,100 m). The glacier flows north down a steep slope and terminates near 9,800 ft (3,000 m). It has a contributing drainage area of 1.03 km2.
The Wintun Glacier is a glacier situated on the eastern flank of Mount Shasta, in the U.S. state of California. It is both the third largest and third most voluminous glacier in California after the neighboring Hotlum Glacier and the Whitney Glacier. The Wintun Glacier starts on the east side of Mount Shasta's main summit, and it has the highest permanent snow and ice on the mountain, reaching above 14,100 ft (4,300 m) to within a few dozen feet of the true summit. The glacier flows east down a steep slope and terminates in two lobes, the longer of which extends down near 9,800 ft (3,000 m).
The Konwakiton Glacier is a glacier situated on the southern flank of Mount Shasta, in the U.S. state of California. It occupies the head of a large cirque on the south side of Shasta's Misery Hill cone, just northeast of the prominent outcrop of Thumb Rock at about 11,500 ft (3,500 m). It is the fifth largest glacier on Mount Shasta, although less than one-third the size of any of the four larger ones. The Konwakiton is the most frequently visited of Shasta's glaciers, since the standard climbing route up Avalanche Gulch skirts along its western edge above Thumb Rock saddle, with the boot track often only a few feet from the bergschrund at the glacier's head.
The Watkins Glacier is a glacier situated on the southeastern flank of Mount Shasta, in the U.S. state of California. It occupies a small cirque in the Clear Creek drainage. It is the smallest officially-named glacier on Mount Shasta, and it was not accorded that status until 1976, following a decades-long campaign by local resident R. Harry Watkins, Jr., to bring recognition to the previously-ignored glacier.
Jorge Montt Glacier is a tidewater glacier located in the Aisén Region of Chile, south of the town of Caleta Tortel. It lies at the north end of the Southern Patagonian Ice Field, within Bernardo O'Higgins National Park. The mouth of Pascua River is located in the vicinity of the glacier calving front.
The tidewater glacier cycle is the typically centuries-long behavior of tidewater glaciers that consists of recurring periods of advance alternating with rapid retreat and punctuated by periods of stability. During portions of its cycle, a tidewater glacier is relatively insensitive to climate change.
Petermann Glacier is a large glacier located in North-West Greenland to the east of Nares Strait. It connects the Greenland ice sheet to the Arctic Ocean at 81°10' north latitude, near Hans Island.
