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Middle Fork Toklat Glacier photo pair
Photo Credits: Stephen R. Capps (1919), Jeffry Hesse (2015)
Ecoregion: Alaska Range Mountains
Change Type: Glacial thinning and retreat
Glacial thinning and retreatAnimation is available
This view up the “middle fork” of the Toklat River shows several significant landscape changes that have occurred over 96 years. The main trunk of the glacier has retreated and thinned. Also glacier ice clinging to the mountains above the main glacier has disappeared leaving only rock and seasonal snow patches. Visible in the photo left foreground, the river has eroded into the vegetated terrace, while on the right, vegetation has grown over the lower alluvial fan. Photographic evidence of landscape change is not the only data available for this glacier. In 2012 and 2015 this glacier was visited by citizen science expeditions to map the terminus and ice surface elevations of the glacier with a high precision global positioning system (GPS). Findings from this fieldwork paired with analysis of topographic maps from 1952 and 2010 show that the glacier has retreated 1.4 km between 1952 and 2015, and that the rate of ice volume loss increased 40% between the periods of 1952-2010 and 2010-2015. The Glaciology Citizen Science expedition is a partnership between the NPS and Alaska Geographic through the Murie Science and Learning Center. To learn more about the expedition go to