DOCUMENTING GLACIER CHANGE IN DENALI NATIONAL PARK AND PRESERVE, ALASKA

Glaciers are a significant geologic feature of Denali National Park and Preserve, currently covering approximately 17 percent or 4047 square kilometers of the park. Highly sensitive to changes in temperature and precipitation, glaciers dynamically react to climatic drivers by thickening and advancing during periods of increased accumulation and thinning and retreating during periods of increased ablation. Alteration of the Denali cyrosphere directly influences the physical landscape, the local hydrologic regime, and the diversity and spatial distribution of biologic communities in the park. Understanding the scale and pace of past glacial system change in Denali provides critical insight into how these processes may continue in the future.

This study utilizes protocols and methods developed by a joint USNPS-USGS study initiated in 2003 to inventory and assess the glacial resources of Glacier Bay National Park, Alaska. During the summer of 2004 the locations of several historic ground-based images made in the early 1900’s by survey and research expeditions to the Denali area were reoccupied and the images were repeated using modern digital cameras. New photo stations were established at locations lacking historical coverage. The geographic coordinates, elevation, general bearing, and photographic details of each location were recorded to expedite future visits. Additionally, helicopter and fixed-wing aircraft were used to make modern analog images of the oblique aerial photos produced in the 1930’s to 1980’s by prolific photographers such as Bradford Washburn and Austin Post. The flight paths and the photo locations (geographic coordinates and altitude) were recorded using technology that links the digital images to a GPS track log. The observations and photo-pairs were combined with data from existing maps and satellite imagery to produce park-wide GIS coverages of glacial extent in the 1950’s and 2000, and bidecadal coverages for several individual glaciers.

Information produced by this study will be used to create several educational products including a website and visitor center display. The GIS data and photographic media will be available to park management and staff, park visitors, researchers, educators, and the general public through the accompanying website.