Glaciers of Oregon
Eliot Glacier, Mount Hood (K. Jackson, 2005)
Welcome to the Glaciers of Oregon website. During the Pleistocene era, the entire Oregon Cascades may have been covered by glaciers forming a small ice cap. Today, however, only remnants of these former times remain. Glaciers are found on the stunning stratovolcanoes of Oregon's Cascade Range and in the rugged and remote Wallowa Mountains of northeastern Oregon. Not only are these glaciers important sources of water to downstream ecosystems and human infrastructure, they are also important shapers of the landscape.
Contents
Glacier Extent
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| MODIS image (04.26.04) acquired from NASA |
There are more than 450 permanent snow or ice bodies located in Oregon, and 60 of these are larger than 0.1 km2. Of these, 35 are named glaciers - 12 on Mount Hood, four on Mount Jefferson, seven on South Sister, eight on Middle and North Sisters, two on Broken Top, one on Mount Thielsen (faintly visible because of its small size above), and one in the Wallowas. The total area of all the snow and ice bodies in Oregon is 43 km2. The five regions of Oregon glaciers are examined further below.
Note: all statistics here are based on USGS 1:24,000 scale topographic quadrangle maps which are based on mapping photography from 1956 to comprised of dates between 1949 and 1994.
The MODIS image displayed above illustrates the areas of higher elevation in Oregon in white (late spring snowpack), while the blue areas are glaciers (these blue features have been added to the MODIS image). The glaciated areas of Oregon range from 43.1 to 45.5 degrees north and -117.1 to -122.1 degrees west.
History
Glacial HistoryDuring the Pleistocene (~1.8 million years BP - 10,000 years BP) the Oregon Cascades may have been covered by glaciers creating a small ice cap (Porter et al., 1983). Scott (1977) inferred maximum glacial extents at Mount Jefferson to have occurred ~20 - 25,000 years ago, which is comparable to those found on Mt. Rainier, Washington. Licciardi et al. (2004) identified two glacial advances in the Wallowas, one at approximately 21,000 years ago and the other at 17,000 years ago. When compared with other glacial maximums from the western United States, the Wallowas illustrate the influence of the Laurentide Ice Sheet on the regional climate. Holocene (~10,000 years ago to the present) glacial fluctuations are better understood in Oregon. Lillquist (1989) identified "Little Ice Age" (a global cool period from about 700 years ago to 150 years ago) moraines on Mount Hood and possibly moraines dating to approximately 4,500 - 5,000 years ago. "Little Ice Age" moraines have also been identified on Mount Jefferson (Scott, 1977), the Three Sisters (Marcott, 2005), and Broken Top (Dethier, 1980; Marcott, 2005). Other moraine sets downslope from the "Little Ice Age" moraines on the Three Sisters and Broken Top place glacial advances/stands at about 2,000 - 3,000 and 4,500 - 6,500 years ago. Another moraine set downslope of these pre-dates 7,700 years ago (Marcott, 2005). Kiver (1974) identified "Little Ice Age" moraines in the Wallowas as well as a morainal advance/stand at approximately 2,000 years ago (Prospect Lake). The moraines from the "Little Ice Age" and earlier dates indicate larger glaciers than presently exist. |
| Early Exploration Coleman (1877) credits the "discovery" of glaciers in Oregon to Lieutenant-Colonel Gordon Granger, who visited the glaciers of Mount Hood in 1840. However, Arnold Hague's descriptions of Mount Hood's glaciers were the first to be published (King, 1871). In 1867, the U.S. Congress passed legislation funding the War Department to survey all lands east of California along the 40th parallel and named Clarence King the geologist in charge. King sent Hague north from San Francisco in August, 1870. Hague examined the glaciers on the south side of the mountain while climbing to the summit in early September. King (1871) is credited with the first "discovery" of glaciers in the American West, during his climb of Shastina (a parasitic volcanic cone on the western flank of Mount Shasta) on September 11, 1870. However, Hague "discovered" the glaciers of Mount Hood at some point between September 4, 1870 and September 18, 1870 (Babson, 1997), and may deserve credit for "discovering" glaciers in the western United States before King. After this expedition, King became the first director of the United States Geological Survey. |
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| Arnold Hague (photographer unknown) | Clarence D. King, 1879 (USGS photo archives) |
| The glaciers of Mount Jefferson were named in 1915 by Ira A. Williams of the Oregon Bureau of Mines in 1915 (Hatch, 1917). Edwin Hodge (1925) of the University of Oregon studied the glaciers and geology of Mount Jefferson as well. The glaciers of the Three Sisters region were "discovered" and described by Williams in 1916 (Williams, 1916). Lathrop Glacier on Mount Thielsen was "discovered" by Dr. Theodore Lathrop in 1966. |
The Mazamas, and Oregon-based hiking club, began glacier monitoring programs on the glaciers of Oregon's Cascade Mountains in the early twentieth century. A number of aerial surveys were flown during the period of the 1930s to the 1950s (see below). Additionally, select glaciers such as Eliot (Mount Hood) and Collier (North Sister) have been studied extensively by the Mazamas Research Committee and through Mazamas Research Grants.
Photographs
 July 23, 1901 photograph of Eliot Glacier (left and center areas of photo), Mount Hood, courtesy Mazamas (H. F. Reid) |
 July 22, 2005 repeat photograph of image on left. Note thinning of glacier and exposure of bedrock (K. Jackson) |
 July 23, 1901 photograph of Eliot Glacier's terminus, Mount Hood, courtesy Mazamas (H. F. Reid) |
 July 22, 2005 repeat photograph of image on left. Note lack of ice on left portion of photo and large increase in vegetation (K. Jackson) |
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| September 15, 1935 photograph of Eliot Glacier's terminus, Mount Hood, courtesy Mazamas (A. J. Gilardi). The terminus is rock-covered and difficult to see (center picture) | July 22, 2005 repeat photograph of image on left. Note thinning of terminus area as well as exposure of Cooper Spur cliff face left of summit (K. Jackson) |
Glaciated Regions
Five areas contain glaciers in Oregon:| Mount Hood |
Mount Jefferson |
Three Sisters/Broken Top |
Mount Thielsen |
Wallowa Mountains |
Mount Hood
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About 148snow and ice bodies are found on Mt. Hood with a minimum elevation of 1295 m and maximum elevation of 3420 m with a mean of 2304 m and an area of 22.7 km2. Of these snow and ice bodies, 12 are named glaciers (all are labeled on the map on the right except Coalman Glacier, located in the crater at the summit) (USGS 1:24,000 scale topographic map, current edition 1996, created from 1956 aerial photographs). Mount Hood is a stratovolcano comprised of mostly andesitic rock. The glaciers of the northern side are mantled with rock debris on their terminus's as a result of frequent rock avalanches from Hood's geothermally altered north face (picture). The glaciers of the southern side are mostly "clean," that is, with little or no rock debris on the ice. Reid (1905) described Hood's glaciers in detail following a trip to the mountain in 1901. The "White Glacier" (now known as the White River Glacier), Coe, Eliot, and Newton Clark were described and photographed. Reid noted that the three northern glaciers (Ladd, Coe, and Eliot) were covered by debris as opposed to those on the south side of the mountain. Eliot Glacier, named after Dr. Thomas Eliot of Portland, Oregon, has been the most studied glacier on Mt. Hood. For more information about the glacier, click HERE. Photos (courtesy of Mazamas):
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Map of Hood created by W.A. Langille, circa 1900 (Reid, 1905)
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 White River Glacier, 1901 (H.F. Reid) |
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| Mount Hood |
Mount Jefferson |
Three Sisters/Broken Top |
Mount Thielsen |
Wallowa Mountains |
Mount Jefferson
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About 35 snow and ice bodies are found on Mt. Jefferson with a minimum elevation of 1877 m and a maximum elevation of 2496 m with a mean of 2496 m and an area of 5.5 km2. Of these snow and ice bodies, four are named glaciers (all are labeled on the map on the right) (USGS 1:24,000 scale topographic map, current edition 1997, created from 1949 aerial photographs). The glaciers of Mt. Jefferson are mostly confined to the north, east, and southeast slopes of the mountain. However, in the early twentieth century a glacier was described occupying the western flank of the mountain and was named "Milk Creek Glacier" (Milk Creek is the area under the "Mt. Jefferson" label on the map on the right). However, as Hatch (1917) stated, it was merely a glacial remnant of "stagnant ice" partially covered in debris. The current glacier coverages delineated on USGS 1:24,000 scale quadrangle maps (see figure at right) do not label this feature. As early as 1917, Hatch (1917) noted that Russel and Jefferson Park glaciers (along with the rest of the mountain) had undergone a recent retreat leaving behind well-defined lateral moraines. Hatch (1917) described Whitewater Glacier as approximately five miles wide and one to two miles long splitting into five lobes. Currently, however, Whitewater Glacier is only about three kilometers (1.9 miles) wide and just over one kilometer long.
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 August, 1917 map of Mount Jefferson created by R.J. Davidson (Hatch, 1917) |
| Mount Hood |
Mount Jefferson |
Three Sisters/Broken Top |
Mount Thielsen |
Wallowa Mountains |
Three Sisters/Broken Top region
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North/Middle Sisters About 78snow and ice bodies are found on North and Middle Sisters with a minimum elevation of 2055 m and a maximum elevation of 3063 m with a mean of 2490 m and an area of 5.4 km2. Of these snow and ice bodies, eight are named glaciers and are all labeled on the map on the right (USGS 1:24,000 scale topographic map, current edition 1997, created from 1957 aerial photographs). Williams (1916) described four active glaciers on Middle Sister: Hayden, Diller, Renfrew, and Collier. Of these, Collier Glacier has been studied in detail. When Williams examined Collier in 1916, he declared Collier was as large, if not larger, than the other glaciers of the Oregon Cascades. In 1910, the terminus of Collier Glacier reached Collier Cone. Since 1910, however, Collier has retreated almost two kilometers and lost over one square kilometer of its area.
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South Sister About 51snow and ice bodies are found on South Sister with a minimum elevation of 2205 m and a maximum elevation of 3142 m with a mean of 2588 m and an area of 4.4 km2. Of these snow and ice bodies, seven are named glaciers (all are labeled on the map on the right) (USGS 1:24,000 scale topographic map, current edition 1997, created from 1957 aerial photographs). The earliest descriptions of past and present glaciations in the Three Sisters were made in 1916 by Ira Williams of the Oregon Bureau of Mines and Geology (Williams, 1916). Williams described that "Lost Creek canyon throughout practically its entire length from where it heads against the slopes of South Sister to its union with the McKenzie, a distance of twenty miles or thereabouts, is deeply glacier cut and its U-shaped cross section is not to be mistaken" (Williams, p. 15). Five glaciers were described on the slopes of South Sister (currently there are 7 named glaciers), all noted to be much smaller than in recent historic times. Many of these glaciers were and still are mantled with rock debris on their lower margins. Williams described (and named) Prouty Glacier as breaking into four fingers of ice, each terminating into a small lake of glacially discharged water. Lewis Glacier was described as splitting into two lobes, the eastern of which ended abruptly in a 40 to 50 ft high ice face which often calved sending large ice blocks down the steep slope the glacier mantled.
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 Unnamed glacier or permanent snow body in South Sister summit crater, 2004 (M. Weaver) |
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Broken Top About 33snow and ice bodies are found on Broken Top with a minimum elevation of 2152 m and a maximum elevation of 2736 m with a mean of 2382 m and an area of 3.3 km2. Of these snow and ice bodies, two are named glaciers (both are labeled on the map on the right) (USGS 1:24,000 scale topographic map, current edition 1997, created from 1957 aerial photographs). Many of the snow and ice bodies on Broken Top exist as a result of topographic shading as these bodies exist at a lower elevation than do those on the nearby Three Sisters mountains.
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  Glacier and moraine-dammed lake to the east of Broken Top summit, 1938 (K.N. Phillips, 1938) |
| Mount Hood |
Mount Jefferson |
Three Sisters/Broken Top |
Mount Thielsen | Wallowa Mountains |
Mount Thielsen
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One ice body (two lobes that are grouped as one glacier--Lathrop) is found on Mt. Thielsen and ranges in elevation from 2498 m to 2601 m with a mean of 2565 m and an area of 0.003 km2 (USGS 1:24,000 scale topographic map, current edition 1998, created from 1994 aerial photographs). Mount Thielsen essentially is a geomorphic feature called a horn. This is a glacially-modified peak, the most famous of which is the Matterhorn. Four cirques surround the mountain almost perfectly leaving four aretes and a horn, a classic example of glacial erosion. Lathrop Glacier was "discovered" in 1966 when Dr. Theodore Lathrop peered from the summit down the north face of Mt. Thielsen and thought the two small snow and ice bodies he saw might be an active glacier. Starting in 1968, Dr. Lathrop's nephew, Ralph Nafziger and others began monitoring Lathrop Glacier's east and west lobes with photographs after repeated attempts at placing stakes in the glacier surface failed.Lathrop Glacier lies in a shady northeastern slot and is the last remaining glacier on Thielsen and the southernmost glacier in Oregon. Click HERE for a photographic record of Lathrop Glacier, donated by Ralph Nafziger of Albany, Oregon.
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| Mount Hood |
Mount Jefferson |
Three Sisters/Broken Top |
Mount Thielsen |
Wallowa Mountains |
Wallowa Mountains
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About 131snow and ice bodies are found in the Wallowa Mountains with a minimum elevation of 2297 m and a maximum elevation of 2898 m with a mean of 2688 m and an area of 1.5 km2. Of these snow and ice bodies, only one is a named glacier (USGS 1:24,000 scale topographic maps, current edition 1990, created from 1981 aerial photographs). The Wallowas were once heavily glaciated, as displayed by large U-shaped glacial valleys as well as cirques (a bowl-shaped depression resulting from glacial erosion). Wallowa Lake is a moraine-dammed lake, the moraines were formed during the last ice age. However, it is highly unlikely that any of the blue areas identified on this map are more than perennial snowpacks. Benson Glacier (below), named for Frank W. Benson, an early governor of Oregon, is located on Eagle Cap (see figure at right), and may still be an active glacier.
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Glacier ChangeThese graphs display the spatial losses of six of Mount Hood's glaciers and Collier Glacier, North Sister. The upper graph presents total areal losses of the glaciers in square kilometers and the lower graph normalizes this data with each glacier's original area set at 100%.
Vanished Glaciers???
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Fun Facts
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Links
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Glaciers of the American West States with Glaciers Portland State University Glacier Research Keith Jackson's Eliot Glacier research Hassan Basagic's Sierra Nevada Glacier Research Back to Contents |
References
Babson, S.G. 1997. Letters from Arnold Hague: early Mount Hood explorer, editor. Oregon Historical Quarterly, Summer 1997.
1Cascades Volcano Observatory Website - Three Sisters Volcanoes, Oregon.http://vulcan.wr.usgs.gov/Volcanoes/Sisters/description_three_sisters.html Last accessed 01-Dec-2005.
2Cascades Volcano Observatory Website - Three Sisters Vicinity - West Uplift. http://vulcan.wr.usgs.gov/Volcanoes/Sisters/WestUplift/ground_uplift_may2001.html Last accessed 01-Dec-2005.
Coleman, E.T. 1877. Mountains and Mountaineering in the Far West. The Alpine Journal, 8:233-242.
Dethier, D.P. 1980. Reconnaissance study of Holocene glacier fluctuations in the Three Sisters area, Oregon. EOS Transactions, American Geophysical Union 61:69.
Grauer, J. F. 1975. Mount Hood: A complete history. Privately printed.
Hatch, L. 1917. The glaciers of Mt. Jefferson. Mazama, 134-139.
King, C. ,1871. Active Glaciers within the United States. Atlantic Monthly, 27:8 March 371-377.
Kiver, E.P. 1974. Holocene glaciation in the Wallowa Mountains, Oregon. In: Mahaney, W.C. (ed.) Quaternary Environments Proceedings of a Symposium: Geographical Monographs No. 5 , York University, Toronto, Canada.Licciardi, J.M., Clark, P.U., Brook, E.J., Elmore, D., and Sharma, P. 2004. Variable responses of western U.S. glaciers during the last deglaciation. Geological Society of America , 32:81-84.
Lillquist, K.D. 1989. Holocene Fluctuations of the Coe Glacier, Mt. Hood, Oregon. M.S. Thesis, Portland State University, Portland, Oregon.
Marcott, S. 2005. A tale of Three Sisters: Reconstructing the Holocene glacial history and paleoclimate record at Three Sisters Volcanoes, Oregon, United States. M.S. Thesis, Portland State University, Portland, Oregon.
McNeil, F.H. 1937. Wy'east "The Mountain" . United States: Metropolitan Press.
Nelson, L.A. 1924. A new glacier on Mt. Hood. Mazama, 67-70.
Phillips, K.N. 1938. Our vanishing glaciers. >Mazama, 24-41.
Phillips, K.N. 1939. Farewell to Sholes Glacier. Mazama,37-40.
Porter, S.C., Pierce, K.L., and Hamilton, T.D. 1983. Late Wisconsan mountain glaciation in the Western United States, in Porter, S.C., ed., Late-Quaternary Environments of the United States, Volume 1: Minneapolis, University of Minnesota Press, p. 71-111.
Reid, H.F. 1905. The glaciers of Mt. Hood and Mt. Adams. Mazama, 195-200.
Scott, W.E., 1977. Quaternary Glaciation and Volcanism, Metolius River area, Oregon. Geological Society of America Bulletin, 88:113-124.
Skovlin, J.M., Strickler, G.S., Peterson, J.L., and Sampson, A.W. 2001. Interpreting landscape change in high mountains of northeastern Oregon from long-term repeat photography. United States Department of Agriculture General Technical Report PNW-GTR-505.
Williams, I.A. 1916. Glaciers of the Three Sisters. Mazama, 14-23.
Back to ContentsLast modified: 08.02.06