Repeat photo image of Jackson Glacier, 1941-2019, Glacier NP.

In Glacier National Park, MT, USGS scientists use repeat photography to document glacier change.  Historic glacier photographs, gleaned from personal and archival collections, are repeated and compared, providing a visual comparison and photographic record. This method of photo documentation complements other quantitative methods of glacier study by the USGS Glaciers and Climate Project, whose aim is to predict and prepare for local, regional, and global implications of changes to Earth's mountain glaciers.