Glaciers in Kenai Fjords NP: Exploration and Change

In 1909, USGS geologists U.S. Grant and D. F. Higgins mapped and photographed all of the tidewater glaciers and many of the land-terminating outlet glaciers in what is now Kenai Fjords National Park, creating a thorough record of glacier terminus positions and heights. In August, 2004, with funding from the National Park Service and the USGS Earth Surface Dynamics Program, we conducted a new photo survey in Grant and Higgins' footsteps. We re-established 40 of their photo stations with a confidence level of approximately 5-30 feet. We located the sites by identifying foreground features and by analyzing the extent of overlap of mountain peaks in the 1909 photo backgrounds. WAAS-enabled GPS was used to determine the location of each station for future surveys. At each station, we took new photographs duplicating the field of view shown in the 1909 photographs and also showing panoramic views. At most locations, the change in glacier height and terminus position since 1909 has been dramatic. At several stations, glacier termini were no longer visible. Northwestern Glacier, for example, has retreated around a series of bends in its valley. In some cases, vegetation completely obstructed the view from the 1909 photo station. In these instances, new GPS-located photo stations were established within sight of the present day termini. To illustrate the changes for the public, a dozen photographic pairs have been turned into animated GIFs using MacroMedia Flash. Each animation begins with a 1909 Grant and Higgins photograph which fades into the 2004 image. The two images have been correlated by matching topographic features. The animations clearly depict changes in vegetation, glacier cover, and geomorphologic features that have taken place in the last 95 years.