This article is provided as a public service by the Geophysical Institute, University of Alaska Fairbanks, in cooperation with the UAF research community. Larry Gedney is a seismologist at the Institute. It is the last of Alaska's 52 tidewater glaciers to begin its epic retreat from the sea.
Glaciers typically follow a seasonal pattern of advance and retreat.
During the late summer months, tidewater glaciers erode on the seaward edge by calving, but if the amount of ice lost is replenished during the winter and early spring months, the glacier remains stable. Mark Meier of the U.S. Geological Survey in Tacoma, Washington, reports in a recent issue of Science News that Columbia Glacier will be reduced to about half its present size in the next 30 to 50 years, and that its terminus will have moved about 40 kilometers up the valley in which it lies. This is an astonishing rate of disintegration. According to Larry Mayo of the U.S. Geological Survey in Fairbanks. In order for the leading edge to actually move backward, therefore, the calving rate in the later months of the year must be phenomenal.