SGER: Columbia Glacier Photogrametry

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Pfeffer0228223This proposal was submitted as a Small Grant for Exploratory Research (SGER) to document to continuing retreat of the Columbia Glacier, in southeast Alaska by rapid calving. The Glacier is presently retreating at a rate of approximately .74 kilometers (km) per year. This rapid retreat has been accompanied by flow speeds up to 33 meters (m) per day, making it the world's fastest-moving glacier. Since 1982, the glacier terminus has retreated more than 13 km since the mid-eighteenth century. It discharges ice into Prince William Sound in excess of 22 km3 . Significant changes may be occurring in the glacier's pattern and speed of retreat during the next year as the glacier terminus passes through a gap which confines its flow. The activities over the next few months may provide important clues about the longer-term fate of Columbia Glacier as the retreat progresses up the channel where the glacier bed lies below sea-level. The Principal Investigators are continuing their analysis of photogrammetric data from 1999, 2000, and 2001 and will submit a proposal to OPP/ANS in August 2002. However, the present terminus position and newly calculated subglacial topography may mean that that the glacier is at a critical state in its retreat, and that significant events may occur before the end of 2002. The funds will allow them to continue the aerial photography through 2002 when important changes may occur as the terminus enters deeper water and passes a major lateral constriction.