Recent Recession and Thinning of Okpilak Glacier, Northeastern Alaska

Sable, E.G.

doi:10.14430/arctic3672

Cited by 10 publications

(8 citation statements)

References 6 publications

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“…Shrub expansion initiated c. 1850–1880 is also supported by direct and proxy air temperature records from Alaska and other Arctic locations showing that warming began between 1850 and 1880, reversing a long-term cooling or stable period before 1850, known as the Little Ice Age [ 1 , 10 ]. Summer warming prior to 1907 is evident from historic photos showing the retreat of glacier terminuses in Arctic Alaska [ 42 ] from their Little Ice Age maximum extents—retreat that had accelerated by 1957 [ 43 ] and continues today [ 44 ]. Increasing mean annual air temperatures 50 to 75 years leading up to the 1950s was also evident in warming permafrost borehole temperature profiles from the region [ 45 ].…”

Section: Discussionmentioning

confidence: 99%

Range Expansion of Moose in Arctic Alaska Linked to Warming and Increased Shrub Habitat

et al. 2016

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Twentieth century warming has increased vegetation productivity and shrub cover across northern tundra and treeline regions, but effects on terrestrial wildlife have not been demonstrated on a comparable scale. During this period, Alaskan moose (Alces alces gigas) extended their range from the boreal forest into tundra riparian shrub habitat; similar extensions have been observed in Canada (A. a. andersoni) and Eurasia (A. a. alces). Northern moose distribution is thought to be limited by forage availability above the snow in late winter, so the observed increase in shrub habitat could be causing the northward moose establishment, but a previous hypothesis suggested that hunting cessation triggered moose establishment. Here, we use recent changes in shrub cover and empirical relationships between shrub height and growing season temperature to estimate available moose habitat in Arctic Alaska c. 1860. We estimate that riparian shrubs were approximately 1.1 m tall c. 1860, greatly reducing the available forage above the snowpack, compared to 2 m tall in 2009. We believe that increases in riparian shrub habitat after 1860 allowed moose to colonize tundra regions of Alaska hundreds of kilometers north and west of previous distribution limits. The northern shift in the distribution of moose, like that of snowshoe hares, has been in response to the spread of their shrub habitat in the Arctic, but at the same time, herbivores have likely had pronounced impacts on the structure and function of these shrub communities. These northward range shifts are a bellwether for other boreal species and their associated predators.

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Section: Discussionmentioning

confidence: 99%

Range Expansion of Moose in Arctic Alaska Linked to Warming and Increased Shrub Habitat

et al. 2016

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“…Okpilak Glacier, photographed by Leffingwell in 1907 (Hamilton, 1965), descends from an unnamed 2435-m-high mountain, about 18 km south of Mount Michelson. In 1958, Sable (1960 examined a number of glaciers in the Romanzof Mountains and revisited several photographic sites occupied by Leffingwell at Okpilak Glacier. Comparative photographs document that the glacier retreated more than 300 m in the intervening 51 years.…”

Section: Brooks Rangementioning

confidence: 99%

“…Comparative photographs document that the glacier retreated more than 300 m in the intervening 51 years. Sable (1960Sable ( ) reports that, in 1956Sable ( -1958, Okpilak Glacier's lateral moraines were 45 m to 63.5 m above the edges of the glacier. In 1907, they ranged from being level to 6 m above the ice.…”

Section: Brooks Rangementioning

confidence: 99%

“…Sable also found that the ratio of ice lost to thinning versus the ice lost by recession of the terminus was roughly at least 25:1. Sable (1960) further states that, "All the smaller glaciers in the vicinity of Okpilak Glacier, for which photographic information from 1907 and 1958 can be compared, show evidence of marked recent recession and thinning." Significant retreat has continued to the present (Matt Nolan, December 2004, University of Alaska Fairbanks, personal communication).…”

Section: Brooks Rangementioning

confidence: 99%

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Late nineteenth to early twenty-first century behavior of Alaskan glaciers as indicators of changing regional climate

Molnia

2007

Global and Planetary Change

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“…These investigations also resulted in two recent papers on glaciation of the north-central Brooks Range (Detterman, 1953;Detterman, Bowsher, and Dutro, 1958), which are especially germane to the present study. During the International Geophysical Year, glaciological and geological studies were conducted in the area east of the Hulahula River (Mason, 1959;Sater, 1959;Keeler, 1959;Sable, 1961). More recently, Stephen Porter (1963) modified the chronology of Detterman and others.…”

Section: Introductionmentioning

confidence: 99%

Quaternary geology of the Mount Chamberlin area, Brooks Range, Alaska

Holmes¹,

Lewis²

1965

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Glaciers originating in the Franklin Mountains of the northeastern Brooks Range advanced in four major Pleistocene glaciations and in two minor Recent fluctuations. (The oldest advance, the Weller Glaciation, covered the foothills and reached the south flank of the Sadlerochit Mountains. This advance is recorded by scattered quartzite and granitic erratics on bedrock ridges and by smooth sheets of till on the middle and lower slopes. These oldest till deposits have been profoundly modified by frost action and by processes caused by gravity. Next, the Ohamberlin Glaciation deposited till sheets and outwash aprons which still retain some of their original form. The end moraine of this glaciation is clearly mappable, and the nioraine-outwash relationship is generally preserved, but minor topographic features have disappeared. The less extensive Schrader Glaciation is represented by ridged lobate end moraines, some of which enclose Lake Schrader. These moraines are marked by a few shallow ponds and low hillocks and by a widely distributed, well-formed assortment of frost features. The last major advance, the Peters Glaciation, did not extend beyond the mountain front. The moraines are fresh, bouldery, and steep sided, and frost features are rare or absent. Modern glaciers have formed two groups of moraines: a slightly weathered single or double moraine several hundred yards from the ice front, and a very fresh moraine in contact with the ice. The development of colluvium, alluvial-fan deposits, terrace deposits, alluvial silt, and stream gravel, although it does not clearly record all climatic changes within the Quaternary, was an important aspect of the present landscape.

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Recent Recession and Thinning of Okpilak Glacier, Northeastern Alaska

Cited by 10 publications

References 6 publications

Range Expansion of Moose in Arctic Alaska Linked to Warming and Increased Shrub Habitat

Range Expansion of Moose in Arctic Alaska Linked to Warming and Increased Shrub Habitat

Late nineteenth to early twenty-first century behavior of Alaskan glaciers as indicators of changing regional climate

Quaternary geology of the Mount Chamberlin area, Brooks Range, Alaska

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