| Summary: | The University Archives has determined that this item is of continuing value to OSU's history. Data collected by the USGS (Tacoma) on Columbia Glacier prior to and during its rapid retreat, are discussed to identify processes that control the calving rate and sliding speed. During the retreat, the rate of calving increased almost seven-fold, but at the same time, the glacier speed increased almost as much so that the actual rate of retreat increased slowly. The calving rate is not simply linked to water depth or ice thickness near the terminus. The only statistically significant correlation found is between calving rate and height above buoyancy. The sliding speed does not obey the commonly-used inverse relation between speed and effective basal pressure, unless basal drag changed during the retreat. The data discussed suggest that the long-term velocity near the terminus of Columbia Glacier is linearly dependent on the height above buoyancy. National Science Foundation Grant OPP-9321556.
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