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The Cryosphere An interactive open-access journal of the European Geosciences Union
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
12 Aug 2014
Review status
A revision of this discussion paper for further review has not been submitted.
A conceptual model of cyclical glacier flow in overdeepenings
J. B. Turrin and R. R. Forster University of Utah, Geography Department, Salt Lake City, UT, USA
Abstract. A nearly four-decade, satellite-based velocity survey of the largest glaciers in the Alaska Range, Chugach Mountains, and the Wrangell Mountains of southern Alaska, spanning the early- to mid-1970s through the 2000s, reveals nine pulsing glaciers: Capps, Copper, Eldridge, Kahiltna, Matanuska, Nabesna, Nizina, Ruth, and Sanford glaciers. The pulses increase velocity by up to 2449% (Capps Glacier) or as little as 77% (Nabesna Glacier), with velocity increases for the other glaciers in the range of 100–250%. The pulses may last from between six years (Copper Glacier) to 12 years (Nizina Glacier) and consist of a multi-year acceleration phase followed by a multi-year deceleration phase during which significant portions of each glacier move en masse. The segments of each glacier affected by the pulses may be anywhere from 14 km (Sanford Glacier) to 36 km (Nabesna Glacier) in length and occur where the glaciers are either laterally constricted or joined by a major tributary, and the surface slopes at these locations are very shallow, 1–2°, suggesting the pulses occur where the glaciers are overdeepened. A conceptual model to explain the cyclical behavior of these pulsing glaciers is presented that incorporates the effects of glaciohydraulic supercooling, glacier dynamics, surface ablation, and subglacial sediment erosion, deposition, and deformation in overdeepenings.

Citation: Turrin, J. B. and Forster, R. R.: A conceptual model of cyclical glacier flow in overdeepenings, The Cryosphere Discuss., 8, 4463-4495,, 2014.
J. B. Turrin and R. R. Forster
Interactive discussionStatus: closed (peer review stopped)
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RC C2085: 'Reviwer comments', Anonymous Referee #1, 17 Oct 2014 Printer-friendly Version 
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J. B. Turrin and R. R. Forster
J. B. Turrin and R. R. Forster


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