Glacier retreat in Glacier National Park, Montana, U.S.A., is one example of land ice loss and glacier change. 6) can reveal whether variations in temperature or precipitation are primary factors for observed changes. /fs/2009/3046/index.html South Cascade Glacier, October 2000. Mass turnover has increased throughout monitoring and the trend of increase has become stronger during the last two decades. Glaciers in continental or interior climates (for example, Gulkana Glacier) exist primarily because cold temperatures result in low ablation. The USGS Benchmark Glacier Program began in 1957 as a result of research efforts during the International Geophysical Year (Meier and others, 1971). Figure 2 shows trends for three “benchmark” glaciers: South Cascade Glacier in Washington state, Wolverine Glacier near Alaska’s southern coast, and Gulkana Glacier in Alaska’s interior. Currently, the volume of land ice on Earth is decreasing, driving consequential changes to global sea level and local stream habitat. Part 1 Glacial “retreat" You will be working with data from South Cascade Glacier, WA, which has been monitored in detail by the USGS since 1959. Aside from the last two groups, most of the glaciers of the North Cascades appear to have been in equilibrium with climatic conditions during the past decades. Mass balance of the coastal South Cascade and Wolverine Glaciers correlate well with the PDO during the first few decades of the period of record, showing the effects of ocean-condition periodicity on glacier health. Retreat of South Cascade Glacier, Washington, during the 20th Century Figure 6. South Cascade Glacier is a large alpine glacier in the North Cascades of Washington, USA. Fifty years of U.S. Geological Survey (USGS) research on glacier change shows recent dramatic shrinkage of glaciers in three climatic regions of the United States. The USGS has been monitoring the mass balance of three glaciers in the Pacific Northwest and in Alaska for nearly 50 years. The glacier retreat was slow up to 1987 a total of 25 m. By 2015 the total retreat has amounted to 520 m. The lower section of the glacier below the lowest icefall is stagnant and will be lost. U.S. Geological Survey, Alaska Science Center This shift most likely was due to a shift in the phase of the Pacific Decadal Oscillation (PDO), which is an ocean-climate oscillation (similar to the El NiÃ±o Southern Oscillation) in which the pattern of ocean surface temperatures and atmospheric pressures in the North Pacific Ocean oscillates on about a multi-decadal timescale. Anchorage, AK 99508. This has led to the retreat of all 47 glaciers we monitor, with four of those glaciers having disappeared. 1). What have we learned so far? The net mass balance of a glacier is the difference between the mass gain through accumulation of snow and the mass loss through ablation. Rapid retreat of glaciers is our region's way of tracking the rapid advance of global warming. Increased intensity of hydrologic cycling provides the simplest interpretation for the trend. Today, the federal benchmark glacier program extends beyond Alaska and includes research at the South Cascade Glacier in Washington state and the Sperry Glacier in Montana. The researchers also compare the satellite images with historical maps and information to determine a glacier’s advance or retreat over the past few decades. Edward Josberger, Research Oceanographer (firstname.lastname@example.org) Mass turnover is estimated by averaging the absolute values of winter and summer balances. Snowy winters would have to occur much more frequently in the future to reduce or reverse mass loss from the glacier. This kind of retreating is the result of climate change which has significantly increased due to … The USGS Benchmark Glaciers each exhibit a long-term trend of increasing mass turnover, which have become more well-defined and stronger from 1985 to 2005. Photos courtesy USGS. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. The project has grown steadily since then to include more glaciers every year. Since 1989, the cumulative net balances of all three glaciers show trends of rapid and sustained mass loss. A glacier that is out of balance with the current climate will grow (advance) or shrink (retreat) depending on how the climate is changing (colder or wetter climate will cause advance, warmer or drier climate will cause retreat). The glaciers on Mount Rainier decreased in area by 21% between 1913 and 1994 (Nylen, 2004). Setting a measurement stake at South Cascade Glacier, Washington. This is exemplified by 2004, when strongly negative summer balances (fig. By custom, the common basis is "meters water equivalent" (MWEQ), which is the thickness of water that would result from melting a given thickness of snow or ice. Josberger, E.G., Bidlake, W.R., March, R.S., and Kennedy, B.W., 2007, Glacier mass-balance fluctuations in the Pacific Northwest and Alaska, USA: Annals of Glaciology, v. 46, p. 291-296. The retreat of … Glaciers gain mass through snowfall and lose mass through melting and sublimation (when water evaporates directly from solid ice). The South Cascade Glacier has been closely monitored by glaciologists studying the effects of climate on glaciers. For all three glaciers, the summer balance records show that consistently more ablation took place during the period from 1987 to 2004 than did prior to 1987. The 50-year mass balance records for these three USGS Benchmark Glaciers show annual and interannual fluctuations that reflect the controlling climatic conditions. The glacier retreated 1.9 kilometres (1.2 mi) in 33 years. G lacier monitoring methodology has evolved over time based on scientific reanalysis, and cumulative net mass balance Sperry Glacier since 200. Figure 6 shows the strong influence of regional climate. Four less active glaciers (Lynch, White Chuck, South Cascade, and "Banded") have continued to retreat, and six stagnant, relict ice masses have undergone considerable losses. FOIA 5). One interpretation of the trend towards increasing summer melt at the Benchmark Glaciers is that climate changes that are larger in scale and intensity than periodic shifts in ocean conditions (PDO) are underway. The least significant retreats among the glaciers studied were for Rabots Glacier in northern Sweden, and South Cascade Glacier in Washington state, with probabilities of 11 and 6 … Between 1958 and 2009 South Cascade Glacier lost nearly a half of its volume.. South Cascade Glacier lost mass at an almost constant rate during the late 1950s to the late 1960s, then gained mass until 1976, and has been losing mass at a fairly constant and rapid rate since 1977. Privacy In accordance with these concepts, figure 7 shows that higher turnover rates occur at South Cascade and Wolverine Glaciers than at Gulkana Glacier. Positive mass balance occurs when accumulation is greater than ablation and if maintained over long periods results in glacier growth. Abstract During climate changes, coastal glaciers are more sensitive to changes in precipitation (or the storm tracks that bring precipitation), whereas interior glaciers are more sensitive to changes in temperature. The mean annual balance from 1984 to 2009 on North Cascade glaciers is −0.51 m/y ().The cumulative balance is −13.26 m, equal to an ice thickness loss of nearly 15 m ().This is comparable to the mean annual balance on South Cascade Glacier of −0.78 m/y (Bidlake et al., 2007). Note how far the glacier has retreated since the 1965 photo below. Glacier retreat results in the loss of the low-elevation region of the glacier. The cumulative net balance is the total loss or gain of glacier mass since the beginning of the study period and is presented as spatially averaged thickness change (fig. 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; which in turn has increased melting and increased the frequency of winter rain and melt events that reduce winter accumulation on North Cascade glaciers. 3). In all, about 25 percent of the ice that melted between 2003 and 2010 occurred in the Americas (excluding Greenland). 2007-5055:70. USGS scientists visit each site in spring and autumn (sometimes more often) to keep a running tally of accumulation and ablation for each stake. The accelerating loss of mass, the weakening correlation with the PDO, and increasing mass turnover likely are the result of changes to warmer and (or) drier climate conditions that are affecting all three regions. and the beginning of the 21st Century. Page Last Modified: Tuesday, 29-Nov-2016 17:33:37 EST, Download the latest version of Adobe Reader, free of charge. Densities of snow and ice differ considerably and before glacier-average thickness changes in each material can be summed to the net balance, the changes must be converted to a common basis. This correlation has weakened during the last two decades, as global average temperature has increased. Play media. These glaciers can extend far down-valley to warm, low elevation regions (sometimes to sea level) where high ablation rates offset abundant maritime snow. moving averages are plotted as lines). Meltwater from the glacier flows directly into South Cascade Lake, which feeds the South Fork Cascade River, which is a tributary of the Skagit River. CANADA. PACIFIC OCEAN. Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers.  It is bordered on the east by 8,261-foot (2,518 m) Sentinel Peak, and is about 17 mi (27 km) north of Glacier Peak in the Glacier Peak Wilderness. Conversely, sustained periods of negative mass balance, where accumulation is less than ablation, results in glacier shrinkage. Canada WA Pacific Ocean Cascade Range South Cascade Glacier Seattle 50 100 200 km The map below shows the extent of the glacier in 1958 and in 2013. UNITED STATES UNITED STATES. This mass balance record is now sufficient to interpret glacier responses to short- and long-term climate changes in the Pacific Northwest, the Alaska Coast, and the Alaska interior. Glacier retreat in Glacier National Park, Montana. A shrinking glacier thins faster near the terminus (the lowest part of the glacier) than near the head (the highest part of the glacier), which is why the terminus retreats up-valley while the glacier head remains in place (fig. The mean ELA is 1,900 m. Water from the basin flows into the Cascade River then the Skagit River. The retreat of glaciers since 1850 affects the availability of fresh water for irrigation and domestic use, mountain recreation, animals and plants that depend on glacier-melt, and, in the longer term, the level of the … Figure 2. The U.S. Geological Survey monitors only four of our nation’s glaciers on an annual basis, two of which are in the Lower 48: South Cascade Glacier in Washington and Sperry Glacier in Montana. South Cascade glacier shows alarming rate of melt The world's melting glaciers Glaciers around the world are retreating at unprecedented rates as temperatures rise due to climate change. The cumulative net mass balance describes long-term trends in the glacier shape and size, that is, whether the glacier is growing or shrinking. U.S. Geological Survey, Washington Water Science Center Glaciers respond to climate changes by thickening and advancing down-valley towards warmer lower altitudes or by thinning and retreating up-valley to higher altitudes. The main trunk of the glacier has a southerly aspect, and is fed by four cirques with west, south, and east aspects. The scientists check snow levels against stakes they’ve inserte… The North Cascade Glacier Climate Project (NCGCP) was founded in 1983 to identify the response of North Cascade glaciers to regional climate change, particularly changes in mass balance, glacier runoff and terminus behavior. This valley glacier occupies roughly one-half of a 6.11-km 2 basin. Learn vocabulary, terms, and more with flashcards, games, and other study tools. It is bordered on the east by 8,261-foot (2,518 m) Sentinel Peak, and is about 17 mi (27 km) north of Glacier Peak in the Glacier Peak Wilderness. Tacoma, WA 98402, Rod March, Hydrologist (email@example.com) Water, Ice, and Meteorological Measurements at South Cascade Glacier, Washington, Balance Years 2004 and 2005. The well-studied South Cascade Glacier shrank by 22% during this time period (USGS), while the Blue Glacier in Olympic National Park saw a terminus retreat of 2% between 1957 and 1997 (Conway et al., 1999). South Cascade Glacier is a large alpine glacier in the North Cascades of Washington, USA. The glacier is located at the head of the Cascade River, which drains into the Skagit River and Puget Sound. Data for South Cascade Glacier are available beginning in 1959 (relative to conditions in 1958) and for Gulkana and Wolverine Glaciers beginning in 1966 (relative to conditions in 1965). Glaciers average changes in climate over space and time and provide a picture of climate trends in remote mountainous regions. At the same time that South Cascade Glacier was gaining mass in the early 1970s, Wolverine Glacier was losing mass. Dominated by a maritime climate, the glacier receives heavy annual precipitation, exceeding 4.5 m in places ( PRISM Climate Group, 2006 ) and is heavily influenced by climate conditions in the Pacific Ocean ( Walters and Meier, 1989 ). This study documents historic BC and dust deposition as well as their effect on albedo on South Cascade Glacier (SCG) in Washington State (USA) through the analysis of a 158‐m (139.5‐m water equivalent [w.e.]) Glaciers in coastal, maritime locations (such as Wolverine Glacier) exist primarily because of high snowfall rates, despite warm low-elevation temperatures. Since higher elevations are cooler, the disappearance of the lowest portion of the glacier reduces overall ablation, thereby ... South Cascade Easton. 3) is located in the North Cascades of Washington. Meier, M.F., Tangborn, W.V., Mayo, L.R., and Post, A., 1971, Combined ice and water balances of Gulkana and Wolverine Glaciers, Alaska, and South Cascade Glacier, Washington, 1965 and 1966 Hydrologic Years: U.S. Geological Survey Professional Paper 715-A, 23 p., 4 pl. In its warm phase, the PDO tends to be associated with more northerly storm tracks, which in the past provided moisture for the growth of Wolverine Glacier at the expense of South Cascade Glacier. 934 Broadway, Suite 300 To see if a glacier is growing or shrinking, glaciologists check the condition of snow and ice at several locations on the glacier at the end of the melt season. South Cascade Glacier (lat 48°22' N., long 121°03' W., fig. Annual data collection occurs at three glaciers that represent three climatic regions in the United States: South Cascade Glacier in the Cascade Mountains of Washington State; Wolverine Glacier on the Kenai Peninsula near Anchorage, Alaska; and Gulkana Glacier in the interior of Alaska (fig. South Cascade Glacier in Washington documented from 1928 to 2003 showing the recent rapid glacier retreating. U.S. Geological Survey These long periods of record provide clues to the climate shifts that may be driving glacier change. South Cascade Glacier lost mass at an almost constant rate during the late 1950s to the late 1960s, then gained mass until 1976, and has been losing mass at a fairly constant and rapid rate since 1977. 4). Glaciers that terminate in a lake or the ocean also lose mass through iceberg calving. The net balance of Wolverine Glacier (yellow bars) tracks the winter balance (blue bars) more closely than the summer balance (red bars), in accordance with its location in a coastal climate. Start studying Case Study of Glacier Retreat: South Cascade Glacier, USA. Glacier Cumulative Annual Balance: The negative trend has Gulkana Glacier is inland and relatively isolated from maritime influences; therefore, the glacier has not responded distinctively to shifts in the PDO and to positions of winter storm tracks. 1928 to 2000 comparison: These photos of the South Cascade Glacier in the Washington Cascade Mountains show dramatic retreat between 1928 and 2000. U.S. Geological Survey Scientific Investigations Report. South Cascade Glacier located in a north-northwest facing valley near the crest of the Cascade Range in northwest Washington state. Figure 4. 4210 University Drive 2). Large mass turnover is typical of coastal, maritime glaciers where winter precipitation and snow accumulation are large. Fairbanks, AK 99701, Shad OâNeel, Glaciologist (firstname.lastname@example.org) 6) resulting from record high temperatures and low precipitation, also set the stage for large, intense wildfires that burned in Alaska. Mass-balance data are presented here in three ways to show different aspects of the response of glaciers to climate: (1) cumulative net balance, (2) seasonal mass balance, and (3) mass turnover. One of the glaciers, the South Cascade Glacier in Washington, has lost nearly half its volume and a quarter of its mass since 1958, U.S. Geological Survey scientists said.
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