The basic goal of IMP is an improved understanding of the underlying causes and timing of iceberg calving and ice-drift processes in order to develop a prediction model that relates iceberg production and movement to ocean tides, glacier runoff and other phenomena. To accomplish this goal, a detailed study of all aspects of Columbia Glacier's current and historic regime was undertaken. A mass balance model of the glacier was developed from meteorological observations collected at nearby weather stations. The model calculates snow accumulation, snow and ice ablation and runoff rates for the past 50 years and relates these variables to the current production of icebergs. The ultimate purpose of IMP is to minimize the navigational hazard in Prince William Sound caused by icebergs that are produced by the drastic retreat of Columbia Glacier.
Large icebergs pose a threat to oil tankers in particular.
Thus, there is an ever-present danger of an oil spill caused by a collision between an iceberg and a loaded tanker. The Exxon Valdez had turned to avoid a large field of these icebergs when it grounded on Bligh Reef in March 1989. Columbia Glacier began a rapid retreat in 1980 after at least 2000 years of slow advance and has remained in a stable position for the past several hundred years. In the early 1970s, US Geological Survey glaciologist Austin Post, who had been observing this and other Alaskan glaciers since 1949, predicted that Columbia Glacier was on the verge of retreating. The rapid and unpredictable changes that Columbia Glacier is undergoing, plus the large number of fast-moving icebergs calved from the glacier that have drifted into Prince William Sound, require a data collection technique with a short time interval between observations.