May 10 (UPI) -- According to a new survey, Montana's glaciers have been rapidly shrinking over the last 50 years.
In 1966, Montana was home to 39 named glaciers -- stable bodies of ice larger than 25 acres, the threshold for what is considered a "glacier." Today, just 26 glaciers meet the definition.
Over the last five decades, those 39 glaciers have shrunk an average of 39 percent and some have lost as much as 85 percent of their mass.
The latest survey was conducted by scientists with the U.S. Geological Survey. The survey included data related to 37 glaciers in Glacier National Park and two glaciers located on land managed by the U.S. Forest Service.
"The park-wide loss of ice can have ecological effects on aquatic species by changing stream water volume, water temperature and run-off timing in the higher elevations of the park," Daniel Fagre, lead researcher and USGS scientist, said in a news release.
"While the shrinkage in Montana is more severe than some other places in the U.S., it is in line with trends that have been happening on a global scale," said researcher Andrew G. Fountain.
Researchers used a combination of aerial images and field visits to track the glaciers' shrinking sizes. Data for the glaciers included in the survey are available at the USGS ScienceBase website.