Glacier recession since the Little Ice Age: Implications for water storage in a Rocky Mountain landscape

Glacial ice is a significant influence on local climate, hydrology, vegetation, and wildlife. We mapped a complete set of glacier areas from the Little Ice Age (LIA) using very high-resolution satellite imagery (30-cm) within Glacier National Park, a region that encompasses over 400,000 hectares. We measured glacier change across the park using LIA glacier area as a baseline and used this to estimate change in glacier area and volume over time. An estimated 146 glaciers existed within the current boundaries of Glacier National Park during the LIA. By 2005, only 51 (35%) persisted. Nearly 90% of LIA glaciers had lost 50% of their area by 2005. This decrease in glacier area equates to an estimated loss of ice volume of 1.52 km3, or 1.37 km3 of water storage, roughly equivalent to 40% of Lake McDonald, the largest lake in the park. Understanding rates of deglaciation and implications for water storage and use can assist local resource managers and downstream communities in planning for change.