Grinnel Glacier, Glacier National Park MT

Grinnell Glacier. The glacier’s surface area was 2.33 sq. km in 1850 and 0.88 sq. km in 1993, the date of the last precise survey.

The pro-glacial Grinnell Lake formed in the 1930’s as the ice receded. It is currently 190 feet deep, while the glacier immediately adjacent to it is 300 feet thick. The buoyancy of the water and the weakening and melting of the ice due to climate warming are responsible for breaking the glacier up into the ice floes seen on the lake. Experts expect considerable destruction of the glacier in the next 10 years and that the ice will be essentially gone in 20 years. It has already lost approximately 90% of its volume since 1910.

In 1850, Glacier National Park had 150 glaciers. In 1968, global warming had reduced that number to just over 50. By 1998, the park had 27 glaciers; that number remains the official count as of this writing, but by next year three more will have been taken off the list. Each of the glaciers is shrinking at the rate of 3 to 8% of its surface area per year. The shrinkage is due to an increase in average annual temperatures and/or a reduction of snowfall. If the present rate of increased temperatures continues, the park will be glacier-less by 2030; if the climate gets no warmer, but stays at current temperatures, the glaciers will be gone by 2100.

SOURCE: Dan Fagre, research ecologist, Us Geological Survey’s Northern Rocky Mountain Science Center. See