Boulder Glacier 1932 vs 1988

boulder glacier 1932

George Grant, Glacier National Park, Montana, Archives, 1932

Jerry DeSanto, K. Ross Toole Archives, 1988

The top image is one of the first to initiate the “Repeat Photography Project” representing the disappearance of glacial ice. Boulder is no longer considered an active glacier. Source: National Park Service

GNP: ~150 present in 1850, most still there when park established in 1910. 26 remain as of 2015 that are larger than 25 acres (a guideline to be considered a glacier). Glacier retreat begins near 1914, responding to industrial revolution. Glaciers have reduced by ~85%. Average area reduced by ~39%

Contributions to the Ecosystem

  • Habitats
    • Flora and fauna
    • Rare and endangered species (bull trout and grizzly bear)
  • Maintain stream flow
    • Release water in late summer and periods of drought to low/no flowing streams
    • Regulates stream temperatures
  • Water storage – Drinking water supply
  • Agricultural practices & recreational uses
  • Timber


  • Disrupts wildlife and aquatic food chain
    • Native fish and aquatic insects (temperature sensitive) rely upon glacial melt
    • Stonefly Larva consumes algae and fungi in sediments (important to glacier food chain)
  • Increase hybridization of native and invasive species
  • Public health
  • Loss of sustained water source
  • Risk of vegetation loss
    • Loss of alpine meadows puts species at higher elevations at risk of losing habitats
  • Agriculture
    • Costs of adaptation
    • Development of technologies and management
    • Availability and timing of water
  • Infrastructure
    • Increasing wildfire
    • Insect outbreaks (mountain pine beetle infestation)
    • Tree disease
    • Earlier snowpack melt and increasing hot days
    • Air quality
  • Cloud development