Methodology

Historic photographs of glaciers were located in the Glacier National Park archives and the images were scanned to create digital versions. Digital copies were printed and taken in the field to match the location of the original historic photograph. Color (kodochrome) and black and white (Tmax) repeat photographs were taken with a 35 mm camera fixed on a tripod. Bracketing was used to obtain the optimal exposure settings. Photo data (shutter speed, aperture, etc.) and field conditions were recorded. GPS units were used to determine the location and photos of the photo point were taken. All technical information is recorded with each photo in USGS archiving software that allows for easy searching and detailed photo metadata. Recording such details will hopefully aid others who may repeat these photos in the future.

Locating exact photo points was often challenging and involved lots of time and off-trail hiking. On one occasion an old trail was discovered which provided the precise photo location. Foreground objects proved to be invaluable in re-locating the location of the original photograph. Photos without permanent site features in the foreground, such as large boulders or rock outcroppings proved to be very difficult if not impossible to locate the exact original photo point.

As an ongoing and expanding project, USGS researchers plan to re-photograph all of the park’s glaciers, as well as many of the alpine meadows, treeline regions, and avalanche paths that potentially have changed in response to climatic shifts. Many panoramic photographs from fire lookouts that were taken in the 1930s have been repeated and will be paired with their historic images in a separate collection to be served on this website in the near future. These photographic collections document the landscape as it exists at the turn of the last two centuries and will provide future park visitors and researchers with a rich visual history of Glacier's changing landscapes.